This is an idea for a very novel type of caseless ammunition
gun. Instead of sticking the propellent behind the bullet,
or molding the propellent around the bullet, our propellent
is fed and handled totally separately from the bullet.
The purpose of this design is to prevent many of the
problems
common to guns firing caseless ammo -- most
notably, cook-off (premature detonation of the propellent
due to heat which the firing chamber absorbed from prior
fired shots).
There are doubtless many ways that this idea could be
implemented, but what I'm specifically thinking of is as
follows:
The bullet makes a seal against the barrel. Furthermore,
each bullet has a rear-facing firing pin built into it.
The propellent is loaded in front of a spring-loaded piston,
with its primer facing forwards towards the bullet.
When the user fires the gun, the piston shoves the
propellent forward towards the bullet.
The primer on the propellent strikes the firing pin on the
rear of the bullet, and ignition occurs.
If the distance travelled by the propellent pellet, during
firing, is long enough, the heat soaked into the combustion
region won't conduct into the region that the next
propellent pellet resides.