I saw a weapon from Nammo that programs a dual purpose grenade to air burst so it can reach behind walls and barriers. It is accomplished with a huge and complicated launcher/controller/programmer that must be vehicle mounted. It works by firing the grenade with an RF signal at the preset range, which is determined by a large rangefinder working on radar (?), RF (?), I don't know. There's a guy in a trailer working it with a joystick. Its very precise but won't be carried by the infantry. I am primarily interested in improving the capability at the infantry small unit level.

My variation is a standard under-rifle barrel launched 40mm grenade but with a twist top, marked in meters, only 4 range choices: 20, 30, 40, 80. It could work by sensing how far it is from a signal source that could be RF or some other signal that falls off at a known rate and is strong enough to reach 80 meters. The transmitting unit is a small bolt-on for the under-barrel grenade launcher any infantryman can carry. Or it might be timed like twisting a kitchen timer, only in milliseconds/meter. Not super precise like the deluxe unit but adds a lot to an assault through blasted forest or urban mazes where conventional grenades can be foiled.
-- minoradjustments, Dec 17 2023

Air Burst Grenade Demo by Nammo 2020 https://youtu.be/BP...si=AqJ0emzB1qjGLzs5
Look how big that thing is... [minoradjustments, Dec 17 2023]

The dedicated unit https://en.wikipedia.org/wiki/XM25_CDTE
Exactly right, but the only shoulder-fired weapon you can carry. [minoradjustments, Dec 19 2023]

M203 grenade launcher. https://en.wikipedi...03_grenade_launcher
[bs0u0155, Dec 19 2023]

Ranged Fuse https://cat-uxo.com...-ffv-441-projectile
Sort of like this, only smaller? [MechE, Dec 20 2023]

So, you set it to 30m. At 25 m, it bounces off a tree branch of the blasted forest and falls to the ground, but you are distracted by other stimuli at the time (incoming, outgoing, people screaming, etc.) The target is successfully engaged by another weapon, but you *thought* it was yours. You move forward, past the original target, but once you've gone 55m, the grenade explodes, killing one of your own medics who was evacuating a casualty.

Not saying that would happen all the time, but you'd want to be very alert to the possibility.
-- pertinax, Dec 17 2023


// At 25 meters it bounces off a tree branch//

This is an air burst weapon. It doesn’t wait, unexploded on the ground. It will go off upon any impact. It would be impossible to be injured by it unless you could run as fast as it flies and be there under it at the moment. In order to injure the shooter the grenade would have to bounce all the way back to him/her. Not impossible but very unlikely. These units are set to explode if they hit something before the range setting is reached. Things can also go wrong with spitballs and standard grenades but we still use them. Risk/Reward.
-- minoradjustments, Dec 17 2023


OK, so it has two fuses - one an impact fuse and the other controlled by this RF signal? Not saying that's bad - I'm just trying to get the full picture.

Also, you may note that I'm not warning about injuring the shooter - with the distance-only fuse, that would be unlikely unless the shooter dropped their rifle - I'm just pointing out that there are two ways that the distance between grenade and launcher can increase beyond the specified distance; there's the case where the grenade moves away from the launcher, and then there's also the case where the launcher moves away from the grenade.
-- pertinax, Dec 18 2023


[pertinax] That sounds cool. Using one as a blocking device. You could leave one, or five, of these grenades in a strategic place as you retreat and when you got far enough away at your range setting it would go off as the enemy rolled over your previous position. You could do this progressively to cover an emergency reposition.

I don’t know about RF or any tech stuff. It seemed likely from the vid that that was being used but I don’t know. If you made the grenade simpler by just setting the time delay on the twist-top and forgot about the RF or whatever, eliminating the transmitting unit, you’d still get most of the benefit from it, with a sacrifice of precision. Precision is great, but at these CQB distances precision is less important than volume and ferocity.
-- minoradjustments, Dec 18 2023


This is the sort of functionality (portable, programmable ranged air-burst grenade launcher for infantry) the military does want. There was the XM25 CDTE, or "punisher", which apparently worked but had issues in practice (too heavy, low ammo capacity) and was cancelled.
-- Loris, Dec 18 2023


Nobody's thought of this? Seems like it would render foxholes and taking cover behind walls obsolete.
-- doctorremulac3, Dec 18 2023


[doc] Yes, there are fragmenting air-burst grenades but not for the individual infantryman with only his standard rifle. There is a dedicated carry weapon that does this with a different ranging method (link), but not for the standard under-barrel grenade launcher. It counts the number of spins and can be set precisely. I’m after a cruder solution that will work for every rifleman with a launcher.
-- minoradjustments, Dec 19 2023


//Precision is great, but at these CQB distances precision is less important than volume and ferocity.//

(Channelling 8th) Only because your human precision takes extended time periods, with the collective's superior targeting and fire control this is simply a waste of ammo.

//Nobody's thought of this? Seems like it would render foxholes and taking cover behind walls obsolete.//

The problem has been around since people have been hiding behind things. The problem came to a head in WW1 when the sheer number of projectiles made not hiding behind objects almost immediately lethal. With everyone hiding, solutions were needed.

Various gas weapons work very well, but if your new weapon makes WW1 participants think it's truly awful, then you've invented a slice of hell. Liquid fuel flame weapons also work extremely well.

Eventually, WW1 settled on the tank + infantry clearout technique after a period of well-controlled artillery and indirect (high trajectory, bullets rain down near vertically) machine gun fire.

Sticking a bigger flamethrower on a tank with a towed fuel bowser was VERY effective in WW2 at clearing even well defended bunkers. You don't even need to burn people, get them soaked by squirting unignited fuel through the firing slots and they quickly get the message and surrender.

//It counts the number of spins and can be set precisely. I’m after a cruder solution that will work for every rifleman with a launcher.//

So the brief is to make whatever round compatible with the venerable m203 <link> I suppose. It's worth considering if the indirect fire sight (shown in <link>) would be up to the job? If not, counting revolutions or just time-of-flight isn't difficult with modern electronics. It would be trivial to make a grenade on which you can set the range, insert, fire. Slow, sure, but you can have several people in a squad equipped with an M203 vs having to give up the rifle for an XM25. For extra credit, have a grenade that explodes backwards/down. Time for a smoothbore m203?
-- bs0u0155, Dec 19 2023


There are AA rounds like those fired by the Oelikon GDF, that use three coils in the flash eliminator. The first two coils measure the muzzle velocity of each round, and the third sets a timer for the fuse for that round, giving a pretty precise range.

I'm guessing an under-slung launcher doesn't have a flash eliminator
-- AbsintheWithoutLeave, Dec 19 2023


[bu0u155] I didn’t follow your comment channeling [8th]. But that is the goal: a 40mm grenade that is fired from the m203 and can be set to airburst within a rough range. Given that the available space for fancy electronic solutions like the 155mm Smart or Bonus rounds is very limited in a 40mm format, the simpler the better. Delay, spins, whatever works. There are vids showing airburst grenades exploding 70-100m from the shooter, and it’s definitely keeping heads down as the assault moves forward. I believe these are fired from a towed or vehicle-mounted unit dedicated to range these shots. Some of them hit trees and blow up, but most do the job they were intended for.
-- minoradjustments, Dec 20 2023


See link. The Carl Gustav has airburst munitions that do exactly the latter (twist to set) version of this. You'd have to scale it down a bit more to work with a 40mm, but it shouldn't be difficult. The time to adjust it is a concern.
-- MechE, Dec 20 2023


[MechE] I don't see the time to set as a big negative. You've got to prep and mark some before the assault, and if you are defending you probably have enough time to set some. You've got to load them by hand, one at a time, so a quick twist to a colored detent shouldn't be a problem.

Yup, that Carl Gustav round baked me. All I've got is a smaller version, just not rocket propelled.
-- minoradjustments, Dec 22 2023


//[bu0u155] I didn’t follow your comment channeling [8th].//

In any discussion about weapons, explosives, explosive weapons or weaponized explosions, 8th of 7 would inevitably turn up an flood the discussion with knowledge, experience and a worrying amount of Borg-themed deprecation. I'm just filling in that gap.
-- bs0u0155, Dec 22 2023



random, halfbakery