h a l f b a k e r yContrary to popular belief
add, search, annotate, link, view, overview, recent, by name, random
news, help, about, links, report a problem
browse anonymously,
or get an account
and write.
register,
|
|
|
This bullet would have a plant seed inside it. It may
be
that battlefields and mass graves will turn into
glorious
forests in not too much time.
Poppies are traditional but I think fruits and nuts
would be nice. Perhaps people would ponder the
forests thus created and decide something
probably
isn't worth fighting over.
multiplanter
Tree_20Planting_20Machine_20Gun
How does your garden grow? Blam blam blam blam! [lurch, Oct 29 2012]
chilly veggies
Plane_20planting
[rayfo] goes not just green, but coool green [lurch, Oct 29 2012]
Plow and plant
Cannon_20seeder
[bungston] thinks in higher calibers [lurch, Oct 29 2012]
Thermal imaging studies of bullets in flight
http://www.advanced...ullet-Heating/1$180
[spidermother, Oct 29 2012]
Ah, here we go...
Bonsai_20Bullets
African or European bullet? [normzone, Oct 29 2012]
Square Cube law
http://en.wikipedia...iki/Square-cube_law
"Thus, just scaling up the size of an object, keeping the same material of construction (density), and same acceleration, would increase the thrust by the same scaling factor. This would indicate that the object would have less ability to resist stress and would be more prone to collapse while accelerating." [Voice, Oct 31 2012]
Maybe we should get [Alterother] one of these...
Cat_20food_20can_20shotgun
[normzone, Nov 01 2012]
Pyrotechnic Planting
Pyrotechnic_20planting
Related idea [csea, Nov 09 2012]
(?) Baked
http://www.flowershell.com
[AusCan531, Mar 09 2014]
Voice and Alterother should try this.
http://xkcd.com/827/
[AusCan531, Mar 09 2014]
It's happening!
http://newatlas.com...dable-bullet/47302/
[Voice, Jan 09 2017]
[link]
|
| |
Unfortunately, bullets get rather hot when fired - more than hot enough to render a seed unviable. |
|
| |
Do you have any data on that, [8th]? |
|
| |
How would a bullet heat up, we ask ourselves.
Well, first because it is in contact with the hot
gases produced by the propellant. These are
presumably at several thousand degrees Celsius. |
|
| |
However, the bullet is in contact with these gases
for only the few milliseconds it takes to leave the
barrel. |
|
| |
Second, it experiences friction with the sides of
the barrel. However, it is probably safe to assume
that the temperature generated at the interface
is lower than the melting point of the barrel, say
1000°C. And the bullet is in contact with the
barrel walls for, again, a few milliseconds. |
|
| |
So, how much heat can be transferred to a bullet
in (say) 2 milliseconds, by a combination of (a)
transfer from hot gas behind the bullet and (b)
transfer from the ?1000°C? interface between
bullet and barrel? |
|
| |
I contend that (a) is negligible (I can move my
finger swiftly through a bunsen flame, exposing it
to hot gases for at least a few milliseconds,
without perceptible burnage). I also contend that
(b) is negligible, based on thermal capacities and
conductivities. |
|
| |
I hencetherefore conclude and contend that a
bullet is not especially hot as it leaves the gun. |
|
| |
It also occurs to me that, in all the episodes of
CSI, Quincy, Columbo, Poirot and the like that I
have watched, it has never been suggested that
bullets are hot when they leave the gun. If they
were, then one could determine whether a person
had been shot from close range by noting the
burns caused by the still-hot bullet. |
|
| |
There are, incidentally, thermal imaging studies of
bullets in flight, which show its surface
temperature to be very high (perhaps 300°C).
However, this is the temperature of the surface of
the bullet within milliseconds of leaving the
barrel. During this time, the frictional heat has
not penetrated the body of the bullet
significantly, and hence only the outermost layer
is hot; when that heat energy distributes itself
through the mass of the bullet, it will cause only a
very modest temperature increase in the centre. |
|
| |
Gentlemen of the jury, the defence rests. |
|
| |
Air friction and deformation (both in rifling and at
impact). Frictional heating at impact. |
|
| |
Based on anecdotal evidence (Mythbusters picking
them up and commenting) bullets retain heat for
some time after impact. |
|
| |
More to the point if the seed is actually in the
center of the bullet, I believe it is unlikely it will
manage to break out while sprouting. |
|
| |
And yet bullet wounds don't normally show burning
or scorching? |
|
| |
Based on direct observation (picking them up and immediately dropping them) bullets retain heat for some time after impact. If dropped into a cup of water, there is a substantial sizzling. |
|
| |
The volume of material in contact with a bullet
wound is high, and the duration of contact, for the
first several inches, is low. This would limit
scorching damage to the first layer or two of cells.
Since the cells are experiencing physical insult
much, much greater than thermal, it is likely not to
present as burning. |
|
| |
// bullets retain heat for some time after impact// |
|
| |
Most of the heat, I would venture to vouchsafe,
comes from the impact, and consequent
deformation of the bullet. |
|
| |
I still contend that a bullet, on leaving the gun, has
a very thin hot skin from friction with the barrel, but
an average temperature only slightly somewhat
above ambient. |
|
| |
You need to know: the muzzle velocity of the round, and mass. This will allow you to calculate the muzzle energy. |
|
| |
Then you need to do the exterior ballistics portion: needs the above, plus distance to target and ballistics coefficient. Or, chronographically measured velocity at target. The difference in energy between muzzle and target all gets lost as heat. Some goes to air; some goes to the projectile; a shape that's good for a projectile is bad for cooling. The ratio is probably more easily measured than calculated. |
|
| |
If you use a cast lead bullet in a .17 Remington (very small mass, not a really good ballistic coefficient) and pump up the velocity to higher-than-reasonable levels (say, 4200 fps) you can get a situation where the bullet will vanish (melted, then torn apart by centripetal force) before it gets to a target 100 yards away. |
|
| |
//I still contend that a bullet, on leaving the gun,
has a very thin hot skin from friction with the barrel,
but an average temperature only slightly somewhat
above ambient.// |
|
| |
The whole heat debate is just a matter of engineering.
Use a metal that fragments upon impact OR doesn't
retain heat well and you're fine. |
|
| |
Realistically I don't think temperature is that much of a problem: if you're going to design a bullet that stays in one piece through the barrel and flight, but disintegrates after it's plowed through a couple of inches of earth, while cushioning the seed against the brutal acceleration and deceleration of being fired and hitting the earth, you may as well make it heat-retardant as well. |
|
| |
// Use a metal that fragments upon impact OR doesn't
retain heat well and you're fine. // |
|
| |
Either one of these qualities alone would disqualify a
material for use as a bullet jacket. Jacket material must
be ductile, a property normally found in soft-ish,
conductive metals such as copper. |
|
| |
The thermal energy is going to be pretty much one half the mass times the velocity squared (the kinetic energy) (conservation of energy says all the energy you didn't get rid of in flight ends up in the bullet hole). So, I think it would be reasonable to make the bullet into a discarding sabot style penetrator. |
|
| |
Somewhere here on the 'bakery, we should be able to find air-dropped icicle planting darts which should be applicable/adaptable. |
|
| |
I second what [lurch] wrote, and was about to write something similar. The bullet consist of a group of atoms all moving in mostly the same direction, during the trajectory the bullet travels. Relative to each other, during the flight of the bullet, those atoms are not especially hot, and this is the temperature described in the first few annos here. |
|
| |
When impact happens, though, the proper way to think of it is in terms of atoms colliding with other atoms. So, while the BULLET may stop moving, even passing on SOME of its kinetic energy in the process, many of the atoms of the bullet will still have a lot of their in-flight kinetic energy --but they are no longer moving in parallel all-together. Each atom now exhibits that kinetic energy as increased random motion relative to the other atoms in the bullet. There will be a very significant temperature rise in the bullet at impact. |
|
| |
Note that even if you protect the seed from the atoms of the bullet, you still have the same problem described above, with respect to high-speed seed-atoms suddenly being forced to stop moving all-together. The seed's temperature will rise at impact even if there was no accompanying bullet! |
|
| |
It's not the seeds that need to be heated.
Many species of pine common to your
Northern hemisphere drop their seeds in
tough casings which only open after exposure
to high temperatures. The same is true of the
Australian species.
Pine cones are fibrous and insulating, to keep
the seeds viable by protecting them from
the heat. |
|
| |
Yes, but it won't be heavy enough to be useful. That's why bullets are made of lead. |
|
| |
For 20 7.62 x 51mm full-jacketed rounds (standard NATO load) fired from an L4 LMG at 50m into clean, dry sand at 11C, examination of the 17 projectiles recovered within 30 seconds after the last round was fired gave a range of temperatures from 122C to 193C using a non-contact thermometer. |
|
| |
The projectiles were still significantly above ambient after 10 minutes of air cooling and caused significant discomfort when touched. Some people just won't be told. |
|
| |
It is not unreasonable based on these figures to extrapolate that the bulk temperature of the projectile in flight exceeds 200C for a significant portion of its travel. The materials involved lend themselves to rapid and and homogenous heat distribution. |
|
| |
Further research is planned, as soon as the existing mess has been cleared up. |
|
| |
Forget the bullet part, just issue the armed forces with seed drills, seed fiddles and the like instead of guns. |
|
| |
Isn't that the Peace Corps ? |
|
| |
//bulk temperature of the projectile in flight
exceeds 200C for a significant portion of its
travel// |
|
| |
Only if you assume that the bullet did not heat up
significantly upon impact. Sand or no sand, that
kinetic energy is going to go somewhere. |
|
| |
The correct way to answer this question would be
to suspend [8th] beneath a hydrogen balloon. As
the balloon rises, someone on the ground will fire
repeatedly at [8th]. At some point, the altitude
of the balloon will match the peak altitude of the
bullet. [8th] can then pluck this bullet from the
air as it peaks, and check its temperature, without
the distorting effects of impact warming. |
|
| |
I am happy to make the balloon available. |
|
| |
We have a simpler scheme. |
|
| |
A batch of bullets are drilled in the base with
a 2mm hole extending 80% of the length. Into
this hole is placed a granular material of
known melting point. The filling hole is then
sealed with a threaded plug to prevent
ingress of propellant gases. |
|
| |
The bullets are crimped into cartridge cases
and sequentially fired at 45 degrees
elevation to give the maximum time of flight.
The target area will not be very large. A
suitable expanse of dry sand should be easy
to locate. This area is searched* by poorly-
paid illegal immigrants equipped with metal
detectors and the recovered bullets are
unplugged and the contents of the bore
examined. If the test material has melted
and recrystallised, this will be immediately
evident. |
|
| |
*Results will be obtained faster if the
retrieval operation is concurrent with the
firing. However, this must be weighed against
the risk of samples being damaged by impact
with human tissue. On the plus side, these
samples will be significantly easier to locate. |
|
| |
Regarding the thermal imaging in [spidermother]'s
link: it shows most of the surface of the bullet to
be at something close to ambient temperature.
The tippiest tip of the tip, and small patches on
the side (presumably those which had been in
contact with the rifling) are much hotter, but
clearly these hot areas are only on the
surfacemost surface of the bullet. |
|
| |
Thus, the great majority of the bullet's mass, and
indeed its core, are at close to ambient
temperature. |
|
| |
// only on the surfacemost surface of the bullet // |
|
| |
Did you read the bit about how conductive metals like cupro-nickel and lead are ? |
|
| |
//Did you read the bit about how conductive
metals like cupro-nickel and lead are ?// |
|
| |
Yes. And while I was at it, I read the Wikipedia
page that says that lead has one of the lowest
thermal conductivities of any metal. Most cupro-
nickels are also very poor conductors of heat. |
|
| |
Did you read the bit in Borging For
Dummies about how you need to think before
writing? |
|
| |
Metals are isotropic. That means that heat will
conduct equally in all directions. Hence, if there
are narrow stripes of heat down the sidey sides,
and a small point of heat at the tippy tip, that
means that the heat has not had time to conduct
significantly in any direction, and remains close to
where it was generated. Thus, your very
argument proves that the bullet in the image has
a cool centre. |
|
| |
By taking thermal masses into consideration, you
will also find that a few narrow, shallow areas of
hot metal will not cause the remainder of the
bullet to become especially hot, even when they
have had time to conduct uniformly. I would
estimate that less than 10% of the bullet's mass is
"hot" (>300°C), which will result in an eventual rise
of <30°C in the core of the bullet, impact heating
notwithstanding. |
|
| |
I'm resting my case again, but if this continues I
may just get one with wheels. |
|
| |
Get yourself one of those golf buggy things - tomorrow, weather permitting, a little ballistic calorimetry will be taking place ... |
|
| |
You seem to be resting your case at a point very near to the muzzle of the gun, which may not be the best... Yes, the temps at that point are probably not seed-killing - but it's not a useful situation because you can't produce a realistic scenario in which the seed is "planted" at that point. (Unless you are travelling in an aircraft, pointing the gun back along your path, and firing the bullet to a velocity near to "at rest" with reference to the planting bed. Or you're waving your "inertia-b-gone" wand...) |
|
| |
I think it's interesting to note that, in those infrared images, the bullet's tip has heated to 170C. It hasn't been rubbing on the barrel, not subjected to burning gasses, it's just air friction - from passing through 5 feet (or slightly less) of air. (3 feet outside the barrel - the other foot-and-a-half to two feet probably don't count, 'cause there's no appreciable mass flow past the bullet.) |
|
| |
I would love to see them show further pictures - say 10 feet and 20 feet downrange. Then you'd get a look at rate-of-change of the various hotspots. |
|
| |
Just as an "it doesn't matter, but...", I kind of doubt their description of the heat-image-bloom at the bullet's base being a "reflection" of the muzzle flash. That would be a diffuse light source, symmetrical aroud the axis of the bullet's flight; the reflection should have an annular component to the phong. I think it's more likely a local hotspot on the metal, and heated gasses trapped in the boat-tail's slipstream. |
|
| |
Anyway, in the duel between [m'lud] and [hisBorgnitude], we're doomed to see no winner because the two of you are talking on different fields of honor. What say we hold all further insults, examples, theories, and mathematics until you come to an agreement about what ballistic point is to be the subject of controversy? |
|
| |
(Decide quickly, and let the weather permit, because I wouldn't want to miss experimental gunfire. I just want it to miss me.) |
|
| |
// the other foot-and-a-half to two feet
probably don't count, 'cause there's no
appreciable mass flow past the bullet. // |
|
| |
Since the obturation is never perfect- at least
in a rifled barrel- some propellant gas does
escape forward of the projectile, and can act
as a lubricant between the bore and the
jacket. |
|
| |
The effect is particularly noticeable in larger
calibre weapons that have a driving band
rather than relying on jacket-to-bore contact. |
|
| |
The velocity of the propellant gas forward of
the ogive is only a little more than that of the
projectile due to pressure piling along the
bore, but is visible in some slo-mo imaging as
a small burst of flame before the projectile
starts to exit the muzzle. |
|
| |
That's a nasty cough there. It's too bad the lack of genetic
diversity in the commune leaves such openings for extinction
events from simple allergies. |
|
| |
You might have noticed that I was talking about frictional
heating of the bullet tip. In that context, the blow-by - which is
certainly of sufficient concern to necessitate driving bands, ball-
patching, gas checks, or wadding, depending on what weapon
you use - isn't going to cause much of a point-specific hot spot
by impingement heating; would you not agree? |
|
| |
//You seem to be resting your case at a point very
near to the muzzle of the gun, which may not be
the best// |
|
| |
The manufacturers of the MaxCo Gatlin' Gro
(which, strangely, we managed to patent under
'first to file' law) guarantee only the viability of
the seed at the point of departure from our
apparatus. We can hardly be held responsible for
the laws of physics once these act outside our
product, can we? |
|
| |
//What say we hold all further insults// And the
fun of that would be? I consider a good argument
with [8th] to be my main form of cardiovascular
workout, especially whilst the junior under-
pantrymaid is on leave. I am sure that his
Borgness also relishes such peer-to-Peer
exchanges. The fact that I'm always right is the
most trifling technicality, I assure you. |
|
| |
Little known fact: The server this site runs on is
actually /powered/ by insults. In fact, given the low
overhead of the Halfbakery, there's actually enough
leftover energy to power a sunlamp for a medium-
sized ficus plant standing next to the server rack. |
|
| |
It's all part of an ambitious project undertaken by
the Goog to develop a clean alternative energy
source fueled entirely by Reddit and 4chan. |
|
| |
Now thinking about Eggbert Flapdoodle, chicken thief. Shot in the ass last week, now with Acorn Squash coming out of his Gluteus Maximus. [+] |
|
| |
Given that many seeds can survive boiling water poured over them (a recommended method to trigger germination for some hard-coated seeds), and impacts up to being struck lightly with a hammer, I would not be surprised if this could be made to work. The seed may need to be coddled in a little insulating wadding. |
|
| |
Military bullets are becoming increasingly lead-free, which changes some of the above analysis. (Aside: to me, that has always been the biggest problem with guns. The 'well, derr!' principle suggests that sending tonnage of neuro-toxic heavy metals fanging about, some of it ending up as fine particles, is basically a bad thing.) |
|
| |
////...we hold all further insults// And the fun of that would be?// We need not have misdirected, poorly thought out insults. Let them be highly topical, yet penetrating; well-considered inconsiderateness, cutting to the quick, through the slow, and onward to the stationery. In short, in the shorts. |
|
| |
//use seeds that only germinate when heated, like wot them Australian plants do// |
|
| |
Actually, studies show it is the chemicals in the smoke rather than heat which prompt germination. You can now buy 'smoked' native seeds here where the seedcase has been scored to allow for easier splitting and have been soaked in water which has previously had smoke percolated through it. |
|
| |
Quite so; although some seed capsules open when heated, thus heat indirectly triggers germination. But many Australian plants' seeds are capable of germinating after being heated. |
|
| |
//the bullet's tip has heated to 170C. It hasn't been rubbing on the barrel, not subjected to burning gasses, it's just air friction - from passing through 5 feet (or slightly less) of air. (3 feet outside the barrel - the other foot-and-a-half to two feet probably don't count, 'cause there's no appreciable mass flow past the bullet.)// I don't see why the bullet's tip would not be heated by the air it encounters while inside the barrel. Such heating is surely caused by compression rather than //mass flow past the bullet//, especially for supersonic bullets. |
|
| |
According to the ballistics information for the 7.62X51 cartridge, as referenced on Hornady's web-site: A 150grn full-metal-jacket bullet fired at a muzzle velocity of 2940fps and a muzzle energy of 2878 foot.lbs will lose 440 fps of velocity and 796 foot.lbs of energy after traveling 200 meters (which is round about average engagement distance in my experience).
|
|
| |
150 grains = 9.72 grams
796 foot.lbs = 1080 joules
Ratio of copper to lead = 1:8 (wild guesstimate)
Specific heat capacity of lead = 0.160 joules per gram.degree
Specific heat capacity of copper = 0.385 joules per gram.degree
specific heat capacity of the bullet = 0.185
volume of cylinder 7.62mm diameter X 200 meter = 0.00912 m^3...
multiplied by 1.2 kg/m^3 (density of air) = 10.95g of air
|
|
| |
So as I see it, we have 1080 joules of energy absorbed between 9.72 grams of bullet and 10.95 grams of air. If we assume equal distribution, we should see a 282.43 degree Celsius increase in the temperature of the bullet caused by friction alone in the first 200 meters of flight. |
|
| |
This is not even factoring in the heat/pressure of combustion or the friction between the bullet and the barrel. |
|
| |
Of course, there are factors I am not accounting for due to ignorance as I am neither an aeronautical nor a thermal engineer... I'm just the poor sonuvabitch shooting the damn thing, but if my physics is anywhere wildly near to accurate; I definitely wont be picking up a recently fired projectile. |
|
| |
Also, as to // Perhaps people would ponder the forests thus created and decide something probably isn't worth fighting over.//, I feel confident that implementation of this idea would only lead to phrases such as "I'm going to plant a forest in your chest", or "Keep running your mouth and there will be a tree where you're standing..." |
|
| |
What [MikeD] said, subject to confirmation by
practical testing. |
|
| |
I did a little practical testing with an M1911 (Kimber
Covert II SOCOM, 7 1/4" bbl), a bucket of
sand, and an engine thermometer, and determined that a
.45 caliber FMJ slug excavated from reasonably dry sand
within ten seconds of firing from point-blank range will
have an external temp of 96-117 degrees F (from a test
group of 14 rounds, ambient temp 68 degrees F). |
|
| |
Most were around 100. The 117 was unearthed
considerably quicker than the others through sheer
happenstance. |
|
| |
For those are questioning why I conducted my test with a
handgun instead of the rifle calibers currently under
discussion, let me assure you that when a high-velocity
rifle bullet impacts a bucket full of sand, it more or less
disintegrates, as does the bucket. That said, I'm absolutely
certain that a 7.62 round is considerably hotter than a .45
leaving the barrel. |
|
| |
// a .45 caliber FMJ slug excavated from
reasonably dry sand within ten seconds of firing
from point-blank range will have an external temp
of 96-117 degrees F// |
|
| |
I have cancelled my order for a wheeled case, and
have instead ordered a small plinth on which to
rest my existing case. |
|
| |
I note that this very modest and seed-friendly
temperature is noted after impact, and hence
includes any impact heating. |
|
| |
I note also that, if the bullet is lead, the core of
the bullet will not yet have equilibrated with the
surface, within the ten seconds or so taken to
retrieve said bullet. |
|
| |
Therefore, the centre of the bullet will be even
cooler than the 96-117°F (36-47°C) of its surface. |
|
| |
In recognition of [MikeD]'s outstanding
experimental efforts in the cause of proving me
right, I hereby offer him [8th]'s best silver teapot,
to be suitably engraved. |
|
| |
I would like to point out, in the interest of further
muddying the waters of this already Guinness-murky
debate, that my trials were carried out under less than
scientific conditions and that, shocking as it may seem, I
have only 250 rounds of .45 acp remaining in my stockpile
and thus committed only two magazines' worth of
ammunition, hardly what I'd call a sufficient quantity for
objective analysis. |
|
| |
Nice Kimber, [Alterother]. I acquired an Ultracarry II, but have since come to regret it, as it's much too pretty to carry and shoot. |
|
| |
And it's difficult to find pine and oak loads for it. |
|
| |
Most Kimbers are too pretty for practical use, which I think
is the ultimate irony of an artfully-designed firearm. I have
a fondness for practicality in most things I own, but I must
admit I tarried a bit over the Raptor and the Eclipse before
selecting the SOCOM (which I now recall is actually the
MDC trim package of Kimber's Covert II model <corrected
above>). I specified
the model for gun nuts like ourselves and for those 'bakers
who want to look up specs like twist ratio, frame
composition, and felt recoil to feed into their anal-
retentive mathematical simulations. |
|
| |
A further thought occurs to me (stranger things have
happened): a bullet from my M1911, fired from roughly
waist-height, penetrates 6-8" of sand. While I'm
no botanist, I do have some experience in the cultivation
of certain species of flora, and to me such depth would
seem rather prohibitive to healthy germination of a seed.
I'll look around on the interwebby for the recommended
planting depth for various tree seeds. |
|
| |
"You're .... Home Economics ...!" |
|
| |
// I have only 250 rounds of .45 acp remaining in my stockpile // |
|
| |
Wow, you really do like to live life right on the edge, don't you ? Respect ... |
|
| |
//penetrates 6-8" of sand// |
|
| |
6-8" deep, or just into a backstop? I would expect
the depth to be relatively minimal, since most of
bullet velocity is horizontal. |
|
| |
Doomsday survival nuts don't like miniguns. They need electric power to drive the feed system and they chew through too much ammo. |
|
| |
Doomsday survival nuts prefer simple, rugged kit; better an accurate single shot bolt-action that can take down your target at 1000m with the first shot rather than a noisy, heavy, temperamental spraygun for 5.56mm ... |
|
| |
// Now I'm wondering whether [AO] is one of them
doomsday survival nuts who solves everything with a gun.
// |
|
| |
Not at all. Those people are crazy. I do keep a modest 'just
in case' stockpile, but mostly I have a bunch of ammo on
hand because a dedicated shooter can burn through 300
rounds on a lazy Sunday afternoon. If it comes down to
defending myself or my home with a gun, statistics show
that I'll only need two or three rounds. If it all went to hell
and I needed to hunt for survival, I could make a single
box of rifle bullets last several years. |
|
| |
What I am is somebody who would be warm, dry, and well-
fed long before the survivalist
idiots figure out that a gun cannot provide
shelter, first aid, or clean drinking water. For that matter,
it can't even provide an edible meal, only the starting
point for one. |
|
| |
// 6-8" deep, or just into a backstop? I would expect the
depth to be relatively minimal, since most of bullet
velocity is horizontal. // |
|
| |
In this case, the penetration was vertical because I was
firing downward into a bucket, which is not a
recommended practice, but it's not particularly dangerous
if
you wear PPE and know
how to handle a weapon safely. |
|
| |
Then, since most fire in combat is relatively level,
I'd expect a bullet hitting ground (the only way
they'd self plant) to cut a long groove, but not that
deep of one. |
|
| |
Good point. I've never used a firearm in combat, and never
will, and in my fervor to collect data for the betterment of
mankind that detail escaped my notice. |
|
| |
Forget about the heat, how many Gs are we expecting this little seed to survive? Several thousand I'd imagine. And not just once, but twice. First when you fire it and then when it lands in your unlucky planting medium. |
|
| |
Even if you have it encapsulated in something to keep the shell from deforming I'd imagine the parts inside the seed would get pretty well scrambled. Remember, shooting a seed inside a bullet is pretty much the same as shooting a seed with a bullet and it is a living thing after all. It might survive but I'd be surprised. |
|
| |
Ehh, I'm going to bun this anyway. WTF. I'm sure the problems could be worked out. |
|
| |
Not quite the same thing. The bullet accelerates over the
entire length of the barrel when fired and decelerates
through the length of however deep it goes into whatever
it hits. Shooting a bullet AT the seed puts all the energy
into crushing it the seed can withstand. |
|
| |
Pretty small difference from where the seed is concerned. It's still in for a pretty rough ride. But yes, I did say "pretty much" anticipating somebody pointing that out. |
|
| |
Like I've said many times though, we can put a man on the moon I'm sure we can put a chrysanthemum in our enemy's head. |
|
| |
Probably not- but there are a whole bunch of people here willing to give it their best shot ... |
|
| |
Maybe if we dip the chrysanthemum in liquid nitrogen
and... |
|
| |
Just fire some seeds and see if they germinate! Pop in a blank (or even a live) round, and stuff some wadding and seeds down the barrel. I'd guess that small and hard seeds would have the best chance of surviving. |
|
| |
Okay, I'll unpack my handloading crap and try it. Stay
tuned. |
|
| |
Poppy or sesame seeds wrapped in a paper
cylinder and packed into a 12-bore plaswad
as as a sabot would have an excellent chance
of surviving in a viable state; but the muzzle
velocity is only about 300 m/s tops and the"
range" is very short. |
|
| |
Seeds like that, along with coarse salt, have
long been used for improvised low-lethality
munitions. |
|
| |
Here's the blow-by-blow of my latest insomniac
experiment: |
|
| |
1- find, unpack, and set up handloading crap. |
|
| |
2- load a tray of twenty .45 acp half-loads, each with six
fresh red peppercorns (hardest seeds I can find in the
middle of the night) packed between discs of die-cut
wadding. |
|
| |
3- prepare six buckets, half-filled with sand, half potting
soil. Arrange buckets on basement floor. |
|
| |
4- find, unpack, clean and assemble my old S&W .45,
'cause I really don't feel like firing peppercorn through my
Kimber and Jenny's Defender is, well, Jenny's. |
|
| |
5- don full PPE including double eye protection. |
|
| |
6- fire one peppercorn round into each bucket. Note
interesting sound and shower of loose soil. |
|
| |
7- go upstairs, explain to Jenny, calm dogs. |
|
| |
8- go back downstairs, sweep potting soil into pile, search
for peppercorns. Five of 36 recovered, peices of several
more. All others presumed KIA. |
|
| |
9- make .45 safe and report findings on Halfbakery over
Kraken on the rocks. Watch several episodes of SeaLab
2021 while drinking more rum. Ponder what to do with 14
low-power peppercorn handloads. |
|
| |
Even with half-loads and protected by wadding,
approximately 80% of my 'hard seeds' were blasted into
itty-bitty pieces. Rest that on your case, M'lud. |
|
| |
I stand in awe of your experimental initiative. |
|
| |
(1) Will the recovered 20% germinate? |
|
| |
(2) What is the germination rate of un-fired seeds? |
|
| |
(3) What happens to the seeds if they are
embedded in gelatin in the rear of a hollowed-out
bullet? |
|
| |
I note that there is a wide variety of shells which
have complex timing and detonation circuits build
into them. I'd expect that a dry seed should be
nearly as robust as well-protected (presumably
resin-potted) electronics. Prototype "smart
bullets" (not shells, note) have been developed
which include not only sensors but also micro-
gyros. |
|
| |
Gelatin (sensu lato) can be harder than glass or softer than jelly, and is biodegradable, so it does seem a good candidate. For that matter, what would happen if you simply shot people with rather firm, seed-filled gelatin rounds? They won't be armour piercing, but, as Mercutio said, 'tis not so deep as a well, nor so wide as a church-door; but 'tis enough, 'twill serve...' Although ironically, with his soul of lead, in his particular case, harder rounds would be indicated ... I'll get my coat. |
|
| |
Right. Now we're getting somewhere … |
|
| |
There are two issues to resolve; the
temperature of the projectile in flight, and
the temperature after deceleration (impact)
where more kinetic energy is converted to
heat. |
|
| |
Critically, the duration of the peak
temperature- akin to Pasteurization- needs
to be established. Seed viability is destroyed
when proteins in the germ are de-natured by
heating. |
|
| |
Move over, Jamie and Adam- new
Mythbusters comin' through! |
|
| |
We are now determined to get the facts on
this one, even if it kills someone. |
|
| |
//I'd expect that a dry seed should be nearly as robust as well-protected (presumably resin-potted) electronics.// |
|
| |
I wouldn't. Electronics are prone to fail due to movement, not loading (compression). Most of the materials involved have fairly high strengths, the issue occurs if they slip. If they are potted, this can be essentially eliminated. |
|
| |
Seeds are prone to fail due to compression, with a relatively low material strength. |
|
| |
sp: //someone// -> everyone |
|
| |
// even if it kills someone // |
|
| |
Unlikely, but if I'm expected to continue my redneck
science some schrapnel cuts are practically inevitable. |
|
| |
BTW, a 2 3/4" 12ga shell with a practice load and
peppercorns loaded into one of those nifty Hornady
stacking sabots results in finely ground pepper, a well-
seasoned basement, and a sneezing fit. |
|
| |
I hesitate to ask for even more of your time [Alterother]
but I wonder if you could repeat the experiments with
small seeds. I think they will perform much better than
larger, hard ones because physics. First softer can mean
tougher and second because of the square cube law |
|
| |
I have some thistle seed that we feed to goldfinches in the
summer. I'm going to a Halloween party tonight, but I'll
load some up tomorrow and try it. The main problem I'm
encountering is that the muzzle blast from my .45 blows
half of the soil out of the bucket, and that is the only
caliber of handgun that I own. I'm thinking of repeating my
surface heat and peppercorn-sowing tests with a .22 and a
5.56 (at a longer, more horizontalish range, obviously).
That will probably take all weekend, but I have the
free time because this is an insomnia week and my
submission agency is currently under water. |
|
| |
There's something to be said for a wife who is not
particularly concerned when woken by gunshots in the
dead of night. |
|
| |
I propose that in the interests of science we take up a collection to provide [Alterother] with an appropriate firearm to perform his testing with. |
|
| |
Have you any specifications we need to meet? |
|
| |
We-ell... In the interest of science, the perfect test
platform would be the FN P90/R in 5.7mm with a heads-up
reflex sight and a threaded
barrel (for secure attachment of various scientific
accoutrements, of course). If a collection is taken to
purchase one, I will graciously accept custody of it... for
science, naturally. |
|
| |
I made up a tray of .45 half-loads each containing 8-10
thistle seeds wrapped in a wisp of cotton (from a surgical
swab) and sandwiched between two wadding discs. This
time, I stood on a stepladder and fired downward from
approx 5' above the bucket, which considerably lessened
the volume of soil displaced by the muzzle blast. |
|
| |
The thistle seeds mostly stayed wrapped up in the cotton,
which made locating them surprisingly easy. Penetration
was 1-3". Upon initial inspection, they seemed intact and
unharmed, but under a microscope at 20x they appear a
bit mashed and fragmented, though still whole (for control
purposes, I based this upon comparison with unfired seeds
from the same bag of bird food). I left two
of the buckets (three shots each) unmolested and put them
under my lights to see if the seeds germinate. I sowed a
few unfired seeds at similar depths as a control group. |
|
| |
I am now working out how to conduct a horizontalish test
using various rifle calibers. If results are favorable we will
move on to germination testing. |
|
| |
This is outstanding: serious experimentation to
evaluate a halfbaked idea. I may purchase a spare
cap, in order to be able to doff it to you,
[alterother]. |
|
| |
Two comments:
1) Are you sure the birdseed isn't treated to prevent
germination? A lot of it is, to prevent spilled
birdseed from weeding up your lawn. |
|
| |
I'm not certain about that, although spilled birdseed does
weed up what passes for our lawn. I'll check the bag; if it
is treated in such a way, germination tests will require a
trip to the hardware store in town. |
|
| |
What was the second comment? |
|
| |
As for any doff-worthy efforts on my part, the pleasure is
all mine. The company that handles my submissions is,
much like the rest of Hackensack, currently dealing with
the aftermath of Sandy, and my bi-polar disorder has
decided that I'm not allowed to sleep this month.
Therefore, I currently have oodles of free time, and a man
can only read andor write so many books before he has to
go shoot something. Jenny is happy to see me handloading
again, because she gets a little worried when I'm not
engaging in high-risk activities and snowboarding season is
a couple of weeks off yet. |
|
| |
Excellent. This confirms the Buchanan family
motto: "Nihil bonum fuit umquam peractae a bene
libratum persona." |
|
| |
My second comment was going to be along the
lines of gelatin-embedding of seeds. I would
imagine that any derangement of the seeds
results mainly from the fact that they start out
fairly loose between the wadding discs; said discs
will be slammed together abruptly upon
detonation. However, there is only so much
experimentation one halfbaker can be expected
to do. |
|
| |
I doff my cap, if not to your experimentation,
then instead to your current state of uppedness.
If only there were some way to get all the bipolars
in sync worldwide, we'd have the solar system
fully explored and colonized in a week (although
we might all then sit around the week after,
wondering why bothered). |
|
| |
Going to great lengths to get the answers to questions no sane person would ask - either that's being a halfbaker, or there's a clinical term for it. |
|
| |
Whence the mutual exclusivity? |
|
| |
Formal request that [max] have no fewer than his full
household staff line up and doff their caps |
|
| |
I will ensure that it is done. I will, however, need to
wait until my chief assistant pyrotechnician has
returned, and has had a short time in which to
master his prosthetic elbow. |
|
| |
All I'm doing is shooting at buckets of dirt, guys. |
|
| |
// Going to great lengths to get the answers to questions
no sane person would ask // |
|
| |
Extremely [marked-for-tagline] |
|
| |
another tip of the hat for you sir. |
|
| |
Okay, here's what I've got: |
|
| |
Setting out to test seed planting via long arms rather
than sidearms presented several obstacles. I moved my
test range to the back yard, where I laid out three 4'x4'
beds on a gentle slope, about 6" of used potting soil atop
wet sand (the whole test area got quite wet at times, and
some of it blew away). During test firing, I spread sheets of
brown paper over the beds to track the path of my shots,
since they would be coming in at roughly fifteen degrees to
the horizontal plane of the bed surface. |
|
| |
It quickly became clear that I had no way to repeat my
surface temp test, so I abandoned that step. |
|
| |
I started with the venerable .22 long, which for those non-
gun nuts following the saga is a small, quiet rimfire round
that your
great-grandaddy used to hunt squirrels or rabbits or
ocelots or whatever. My test platform was in fact my
father's childhood squirrel rifle, a well-loved Winchester
Scout. For the ammunition, I loaded two test trays of
crimped 'blanks' with seeds embedded in the wadding
(which I spray-painted Safety Orange for extraction
purposes). The first tray consisted of red peppercorns (two
per round, also painted orange), the second of thistles (6-9
per round, wrapped up in a little wisp of cotton that I dyed
with a pink hi-liter). I also loaded a 'control tray', which
consisted of empty wadding with the same charge,
intended only to test excavation methods. I composed the
powder charge on the light end of a normal .22 load. |
|
| |
I fired from a bench rest at a range of 15'. The peppercorn
rounds had better ballistic and terminal performance,
consistently settling at approx. 3" vertical depth. 25 out of
the forty peppercorns fired were located and all appeared
undamaged, though most had shed their inner calyx, which
is part of the spice flavor but in my experience does not
harm most
seeds. |
|
| |
The thistle rounds I fired from 10', guessing (correctly) that
the wadding and very light seeds would not fly straight. I
recovered only seven of 20 payloads. Most of them
contained only two or three seeds, but these appeared
undamaged both to the naked eye and under
magnification. |
|
| |
Next I stepped up to the 5.56 NATO, a high-velocity round
used in the M16 assault rifle. My test platform was a
Bushmaster AR-15 (a semi-automatic variant of the M16)
with a 21" free-floating heavy barrel, a trusted rifle which
I used in V-MATCH competition for many years. The first
problem with this much more powerful round, which I
anticipated, was that the wadding from blanks in that
caliber is frequently blown into little pieces and never flies
in a straight line. Nevertheless, I loaded up a tray of
peppercorn rounds (three in each round, sandwiched as
usual) and fired them from a range of 15'. 4 out of twenty
hit the target, but I did not recover a single payload. |
|
| |
Going back to my basement, I used a leather punch to
hollow out two wadding discs, glued them together,
loaded two peppercorns into each and capped both ends
with solid wadding discs, gluing the whole thing with CA
glue and painting them orange. These I stuffed into half-
load blanks and crimped them just enough to hold the
payload in place. Loading each round into the chamber by
hand, I fired from 15' and recovered 14 payloads. As I had
hoped, most of my wadding cylinders split open on impact
but still contained their payload. They completely
penetrated the potting soil layer and burrowed into the
sand below, to a vertical depth of 7"-9". A few of the
peppercorns split or crumbled, but most appeared
unscathed. |
|
| |
I repeated this technique with the thistle seeds, recovering
16 of 20 rounds fired. This time the delicate seeds
remained intact but were obviously damaged by the
extreme forces incurred in firing. A small number of them
appeared viable, although the hulls still exhibited the
'mashed' appearance under the microscope. |
|
| |
Just out of curiousity, I loaded a tray of 6.8mm spc, 10
peppercorn and 10 thistle. The resulting massacre does not
warrant reporting. |
|
| |
Make of this what you will. Unless anyone has a fresh idea,
I think I'm done. |
|
| |
[MB], the thistle seeds I've been using are indeed the non-
growing kind. I've just returned from the hardware store,
where I picked up a packet of wildflower seeds for viability
testing. I plan to load them in .45 brass and sow them using
the bucket method, which I will then place in my grow
room alongside a hand-sown control group. |
|
| |
I'm busy again, but I'm still not sleeping much, so I'll
probably load and fire the rounds tonight. Germination
should take less than a week. |
|
| |
You know, this ought to be published somewhere.
Possibly as evidence. But certainly published. |
|
| |
So, are we awaiting sprouting news from The
Germinator? |
|
| |
Storebought peppercorns generally won't sprout anyway. |
|
| |
I would be curious about the other. |
|
| |
I wasn't counting on the peppercorns to sprout; they served
as a stand-in for hard and durable seeds, used for the
sowing tests. The thistle seeds were leftover bird food,
which Lord Buchanan correctly observed had been
sterilized in order to not make a mess of weeds under the
bird feeder. |
|
| |
The results of my germination tests using storebought
wildflower seeds will be published within a week or so.
The control group will definitely sprout (if a plant won't
grow under my lights, it won't grow anywhere), so we'll
have a solid comparison to the viability of the handgun-
sown group. |
|
| |
There's a small business for you. I'll buy your custom handloads. Probably have to ship you some of our natives so as not to introduce non-native species in our few remaining rural shooting ranges. |
|
| |
This is outstanding. There should be a HalfBakery
Award for Experimental Recklessnessness, and I
nominate [Alterother]. |
|
| |
Please, you're all too kind. It's not about me, it's about the
'Bakery. Also, I was bored. |
|
| |
I'll take the award just the same. |
|
| |
I disapprove the nomination, and move to rescind it. |
|
| |
[Alterother] is a trained professional, with adequate experience in the field such that reduces the risk to so low a level as to eliminate the element of recklessness. |
|
| |
However, I'm willing to concede that his actions warrant a Meritorious Conduct for being arsed to follow up on something. |
|
| |
(Sorry, [Alterother], but I didn't want them to confuse loading and firing weaponry at home with recklessness. You know how the unarmed can become confused over simple verbiage) |
|
| |
I think you'd have to ask the seeds about the
recklessness of this undertaking. I'm pretty sure it's
not entirely reckfull from an earthworm's
perspective either. |
|
| |
The only professional training I've had is as a welder,
[norm]. My firearms knowledge is all self-taught or the
result of casual mentorship. I don't even go so far as to call
myself an expert, so don't try to rain on my parade by
pointing out that I sort of know what I'm doing. |
|
| |
Well, in the face of this testimony I must reluctantly withdraw my previous objection. Although the nominee does appear to be undervaluing himself at this moment, his statements allow me to endorse the nomination as previously submitted. |
|
| |
Let me know when the parade is scheduled - can we do it when the weather is nice? |
|
| |
I wonder if the big explodey rockets (fireworks)
could be made to disperse seeds? Or (if you really
don't like any of your neighbours) kudzu cuttings. |
|
| |
If you can eject a parachute you can eject seeds. |
|
| |
Fireworks should be much simpler than bullets. The
forces and heating (except for the bit that
is actually burning/exploding) are much lower. Put the seeds to the
outside of the warhead so they're ejected before
the sparks ignite, and it should work fine. |
|
| |
//Fireworks should be much simpler than bullets.// |
|
| |
My thoughts exactly. See my first Halfbakery posting [link]. |
|
| |
Germination study underway. I'm going out of town next
week, so my results will be published sometime after the
18th. |
|
| |
Excellent - the 18th it is. I'm mildly surprised that
the sentence was so short. |
|
| |
I got home earlier than expected. The control group is
flourishing. The test group has yet to
germinate. |
|
| |
//I'm mildly surprised that the sentence was so short//
The first sentence was only 3 words but the second was 17 words. |
|
| |
I'm declaring this myth bus... Oh, wait, wrong site. |
|
| |
Just to make sure, I dug up the seeds from the test group a
few minutes ago and I actually found two (out of approx.
60
seeds 'sown' in 9 shots) that had begun the first phase of
germination, but they were withered and I doubt very
much if they were metabolizing properly. Still, that's
something. |
|
| |
A few others had pushed out of their calyxes/hulls, but
that's not a sure sign of germination, as it is simply a
matter of expansion as the planted seed absorbs moisture. |
|
| |
This idea is currently No 1 on Reddit. [link] |
|
| |
They should be paying me for all the preliminary research. |
|
| |
Try your luck [Alterother]. [link] |
|
| |
You could pack your fruit pips into bullets to be
planted this way. Eats, shoots and leaves. |
|
| |
Did a search of "how hot is a bullet after it's fired" hoping to find an answer in the form of a number. 300 degrees F, 200 C, or the like. Wow, wow, wow. I previously posted a thinly veiled rant about what I call "squidding", that is, the posting of long winded non-answers on question forums like Yahoo Answers. (squids squirt gobs of obscuring ink, hence the analogy to typing lots of words that say nothing.) |
|
| |
I have never, never, never found a question that requires a number for an answer being answered with such squidding. Here's some of the DOZENS of people without a clue as to how hot a bullet is after it's fired sharing their scintillating insight anyway: |
|
| |
Non-answer #1:
"This is a complicated question due to the number of factors that would contribute to a transfer of heat energy. Furthermore, you would have to specify a projectile and powder charge and a given barrel length and ambient temperature readings for every case." |
|
| |
Non-answer#2:
"how hot do the following bullets calibers get when they are flying thought the air... "
They are already hot. Flying thru the air cools them off a tad." |
|
| |
Non-answer#3:
"Powder ignites hot enough to destroy barrel steel, for a moment.
But that only lasts for a few milliseconds. Someone better at physics should answer that" |
|
| |
Anyway, after much sifting through this kind of blather, I found somebody who said about 500 degrees F who said they had read about measurements being made with actual mesaurement devices. Sounds about right. |
|
| |
I can believe that the *surface* temperature of
the bullet is extremely high, but not the core
temperature. |
|
| |
Clearly, the outside of the bullet isn't hot enough
to melt, otherwise those nice guys at CSI wouldn't
be able to do all that clever stuff. |
|
| |
So, if the bullet is made of lead (are they still?),
its surface temperature when it leaves the barrel
must be at most 330°C (600°F). |
|
| |
I'm assuming it spends maybe 1msec in the barrel. |
|
| |
So, if you heat the outside of a bullet to 330°C for
one thousandth of a second, how hot does does
the middle get? |
|
| |
So yes, the outside of bullet is very hot when it
leaves the gun, and the inside (the great majority
of the bullet by mass) will be at ambient. The
mass-average temperature will be something like
warm. |
|
| |
On impact with a solid, hard target, however, the
bullet's kinetic energy (about 0.5kJ) will be
converted mostly into heat as the bullet deforms.
If this 0.5kJ is spread evenly throughout the
bullet's mass, given a heat capacity of about 4J/g/
°C for lead, it will raise the bullet's temperature
by about 60°C. This assumes a bullet velocity of
300m/s. If the velocity is twice that, the
temperature increase on impact will be about
240°C. |
|
| |
I'll just throw in that lead is an excellent conductor of heat. I'll leave out that bullets aren't all made of lead these days. |
|
| |
// Powder ignites hot enough to destroy barrel steel, for a
moment. But that only lasts for a few milliseconds // |
|
| |
The boundless stupidity of that statement speaks volumes
about the evolving human condition. |
|
| |
How did I miss all this fun back in 2012? What a fine mix. My
favorite:
/If you use a cast lead bullet in a .17 Remington (very small
mass, not a really good ballistic coefficient) and pump up the
velocity to higher-than-reasonable levels (say, 4200 fps) you
can get a situation where the bullet will vanish (melted, then
torn apart by centripetal force) before it gets to a target 100
yards away./ |
|
| |
What a great SF short story this principle would make. I am a
little concerned that liquefied droplets from the original
bullet might still impact on the target, which would be
stingy. |
|
| |
I'm not sure what was meant by "ballistic coefficient," but
'ballistic profile' is a term often bandied about when
discussing cartridge performance, and the .17 HMR is
considered to have a pretty good one. On a windless day
my 77/17 shoots flat as a pan out to around 200 yds. |
|
| |
As for the bullet tearing itself apart at 4200 fps...I can't
disprove it, but I'll only believe it when I see it happen. |
|
| |
//I'll just throw in that lead is an excellent
conductor of heat. I'll leave out that bullets aren't
all made of lead these days.// |
|
| |
I don't think that affects the argument much. The
point is that lead bullets (even though lead may
not be used nowadays) survive without significant
meltage of the outer surface. |
|
| |
That tells you that the surface of the bullet isn't
heated to more than 330°C. Change the metal of
the bullet and, give or take, its surface
temperature on leaving the barrel won't be that
much different. |
|
| |
So, regardless of the bullet material, its surface is
heated to a few hundred °C over a period of a
millisecond. Even for a very good thermal
conductor, I'll put money on the fact that if you
heat the surface for one millisecond, the vast
majority of the interior will still be at ambient. |
|
| |
To take a very simple example, hold a few-inch
piece of copper pipe in a gas flame. How long
before it becomes hot in your hand? A few
seconds? A second? Not less than a second. That's
how long it takes heat to travel a few inches in a
good conductor. So how far does heat travel in
1/1000th of a second? And so, how hot is the
inside
of the bullet as it leaves the muzzle? It's at
ambient. |
|
| |
If *all* of the kinetic energy of 10g bullet starting at
300m/s is converted into heat, and if *all* of this
heat ends up in the bullet rather than the air, that
will raise its temperature by about 50°C. |
|
| |
I suspect that the correct value for *all* is <0.25 in
each case. |
|
| |
Bear in mind also that bullets are* designed to minimize air
resistance. The really good ones are made in a style called
'boat-tailed'** that create a slipstream and a stable wake,
eliminating a great deal of the turbulence that can build up
behind a bullet as it flies. |
|
| |
* and have been for last 150 years or so |
|
| |
** because the rear of the bullet is slightly tapered rather
than squared off, giving it a shape resembling the bird's-eye
profile of a sleek watercraft |
|
| |
[Alterother] - about the melting .17 bullets - I'll
admit that I wasn't an eyewitness. It's something
I'd heard from my pa, about the times when he
was knocking about with P.O. Ackley. (He being
the creator of the "Ackley Improved" wildcat
calibers, which you can find readily on-line;
particularly see the ".17 Ackley Bee". [I had a
Ruger M77 .257 Ackley Improved he custom made
for me. Traded it off to Pa for a .222 Remington
Sako Vixen and a Honda 360. I was young and
dumb]) |
|
| |
Anyway, when they were doing a lot of testing,
they found they could save a few pennies by
adding plumber's solder - the kind you could get in
the 1 lb bars - to their lead pot, and throwing in
some wheel weights. The plumber's solder was a
50/50 lead-tin mix; the wheel weights were 95%
lead, with about 3% antimony and 2% tin. So they
didn't have a really high precision alloy, but they
tried to get close to 90% lead (for the density), 8%
tin (for lowering the melting point), and 2%
antimony (to make the bullets harder, to resist
deforming when pushed into the cartridge neck). |
|
| |
Anyway, if you run the numbers, a 20 grain bullet
(that's about 1.3 grams) travelling 4200 fps (that's
1280 m/sec) has a kinetic energy of about 1062
joules. The exact heat capacity of their alloy
would be hard to pinpoint, but would be in the
range from 0.15 to 0.24 joules/(gram Kelvin); I'll go
middling for 0.2 j/(g K). |
|
| |
That means 1 joule of energy would suffice to
raise the temperature of 1 gram of bullet by 5
Kelvins. It would raise 1.3 grams by 3.85 Kelvin;
1062 joules would be enough to (theoretically)
raise 1.3 grams of that alloy by 4085 Kelvins. |
|
| |
The eutectic point (that's not exactly a "melting"
point, but a point at which the alloy partially
liquifies, leaving it with zero tensile strength) of
the lead-tin solder is about 183 degrees C. That's
about 160 K from ambient. So, yes, the numbers
bear it out. |
|
| |
(Also, the bullet molds they used were not boat-
tailed - they were more of a semi-wadcutter
design, to make a compact bullet that wouldn't
take up as much space in the cartridge neck,
making more room for powder. They were looking
for maximum muzzle velocity at the
time, trying to get a bullet above 5000 fps. by any
trick possible. Downrange performance wasn't part
of the project.) |
|
| |
All of that makes sense, but I'm still skeptical about the
mid-air disintegration. Disintegrating upon impact,
absolutely--even pellets out of my Tech Force (an
impressive Chinese-built air
rifle, for the uninitiated) liquify against a steel target.
Also, my own hot load
experiments have shown me that any bullet under 33
grains will destabilize at around 3000 fps regardless of
caliber (I even necked some .22 shorts into 5.56 brass one
time, with predictable results). I haven't been
able to get anything heavier moving that fast. As far as
ballistic science goes I'm a weekend dabbler at best, so
maybe someone else has better data. |
|
| |
^Perhaps you need more of a twist ? give it more spinny properties. |
|
| |
If you give it more rotation than 1:5 the bullet likely won't
even make it out of the barrel. Almost all of the resistance
a bullet encounters after firing (but before impact) is from
contact with the lands. |
|
| |
There's probably an optimum rotational energy, given weight and dimensions, to poke through the air without tumbling. Firing two identical-sized bullets out of the same firearm, the heavier one will have more RE. |
|
| |
soo.... .22LR hollow-point ? rather than a Short. |
|
| |
Based on casual knowledge of military and hunting
long arms I'd say the rotational sweet spot is somewhere
around 1:9. I don't know as much about sidearms where I
could guess at the average twist ratio. |
|
| |
//Change the metal of the bullet and, give or take,
its surface temperature on leaving the barrel won't
be that much different.// |
|
| |
This probably isn't true. Remember that the bullet
is deformed during firing, and is experiencing
friction in the barrel. The energy it takes to do that
to brass is going to be higher than for lead, and even
higher for some other materials. |
|
| |
Copper has been the jacketing material of choice for over a
century. Gotta be a good reason for that. |
|
| |
Is it copper? Not brass? Or does brass count as copper. Good looking gussied up copper? |
|
| |
Nope, copper. Once in a while you find something jacketed
in a proprietary copper alloy (such as Speer Gold-Dot
hollow points or the infamous and long-discontinued Black
Talon), but nearly all jacketed rounds are and always have
been made with copper. |
|
| |
Military puts copper jackets on the lead bullets. I think copper is a bit more squishy, like lead, than brass. Nothing to do with the shell casing which is pretty well always brass. |
|
| |
There is a trend towards all-copper ammunition for hunting, in an effort to reduce the amount of lead finding it's way into harvested meat and animals that consume gut piles from same. |
|
| |
This trend could pose a heating challenge to the goal of seed planting via firearms - alternate materials may be required. |
|
| |
Really ? I thought copper-jacketed rounds were banned from hunting. |
|
| |
Maybe in Canadia, although I can't imagine why. Nosler-
tipped rounds (a fancy form of hollow point, essentially)
have become the standard choice for deer
hunters, with good reason, and the design would not be
possible without a copper jacket. |
|
| |
I know that hunting with full metal jacket rounds has been
banned in some places because of the blow-through issue,
but the soft tips and hollow points used instead are still
copper jacketed. |
|
| |
//weekend dabbler// I've shot .22 "Accelerators": saboted round in a .308 cartridge. (IIRC) flat trajectory out to 300m then drops like a rock (which'd be when it starts tumbling). Wikipedia says >4kfps for the .30-06 version... that's 55gr though. |
|
| |
Interesting that it flies straight until a certain point--most
bullets I've seen destabilize (free of external influence) do
so almost immediately. You can tell by watching the "bullet
trail" through a scope; a true shot almost looks like
somebody drew a straight line in the air with a pencil,
while a tumbler looks like heat mirage in the wash of a jet
engine. I've never seen one go straight and then tumble. |
|
| |
I wonder if there's a physics foible which causes a bullet
that would fly true at 2000 fps to violently destabilize as it
slows
from twice that speed. Maybe it's to do with air density and
resistance effect on a spinning object, or if the Accelerator
.22 really does cause the round to deform as [lurch]
describes. |
|
| |
The gyroscope effect is what keeps the bullet from tumbling in the air soup it's pushing its way through. |
|
| |
Assuming that, when the forward velocity is halved, the spin velocity is also halved (which it probably won't be, exactly, but whatever), then the halved original aerodrag is being battled by only a quarter the original gyroscopic effect (RE = œmv²). |
|
| |
[edit: ah you're talking about something else'ish...] |
|
| |
The US military is now trying to make this idea come to (heh) fruition. Linky |
|
| |
The selection of seeds is quite specific to the area/conditions
to where they will be planted. I could see the logistical issues
getting out of hand here: "Bloody Supply! They sent us sent
us ammunition requiring cool summers with plenty of rainfall
shells when we're mobilizing tomorrow to the Middle East
again." Meanwhile, the cacti and succulents are deployed
into Scandinavia for the 'Operation Winter Shield' exercise. |
|
| |