The HK G11

Caliber: 4.7 mm caseless
Action: Gas operated, rotating breech
Overall length: 750 mm
Barrel length: 540 mm
Weigth: 3.6 kg empty
Magazine capacity: 50 or 45 rds

Rate of fire: ~2000 rounds/min. (3-rounds burst)

The German government decided at the end of the 1960's to replace the G3.

The initial studies lead to the idea of the small-caliber, rapid-fire rifle that fires caseless ammunition. To ensure sufficient stopping/killing power for small-caliber bullets used, the rifle should had have the three-round bursts capability and high capacity magazine.

Early prototypes featured one 50 rounds polymer magazine, while latest versions featured 45 rounds magazines - one in the loaded position within the movable housing and two spare magazines on the top of the rifle, asides from the loaded magazine.

 The rifle features unique cylinder breech/chamber system that rotates 90 degrees. The cartridges in the magazine are located above the barrel, bullets down. Prior to each shot, first cartridge is pushed down from magazine into chamber and then breech/chamber rotates 90 degrees to align the cartridge with the barrel (see pic).

The firing cycle process is roughly:

-As the cocking handle on the side is rotated clockwise by the weapon operator

-A round is dropped into the revolving chamber vertically (a loading piston assists this process).

-The chamber rotates 90° until it is lined up with the barrel. This completes the chambering of the round and cocking of the firing pin.

-When the trigger is pulled, a firing pin ignites the primer, which then ignites a powder booster charge that pushes the bullet into the barrel. The solid block of propellant is broken up to increase the ignition surface area and ignites, accelerating the bullet out of the barrel.

 -As the projectile is accelerating up the barrel, recoil forces drive the barrel, magazine, chamber and operating mechanism rearwards within the weapon, dissipating energy for single shot and fully automatic modes but allowing burst mode to deliver three projectiles downrange before buffering occurs.

 -Gas tapped off from the barrel rotates the chamber and actuates the loading mechanism then rotating the chamber back to the vertical original position until it is lined up with the feed mechanism and the process repeats.

The caseless ammunition in its early appearance was designed as a block of the propellant, coated with flammable laquer, with bullet and primer "glued on" the propellant. Final ammunition design DM11, that appeared in the mid-1980s, featured "telescopic" design, when bullet was fully enclosed in the block of the propellant. The cartridge propelled the bullet that weights 3.25 gramms, to the 930-960 meters per second.

Early prototypes were prone to the ammunition cook-offs during the sustained fire, but later Dynamit Nobel solved this issue.

In the late 1980s the Bundeswehr (West German Army) began the field tests of the pre-production G11s. After the initial tests, some improvements were devised, such as removable optical sight, mounting of two spare magazines on the rifle, and bayonet/bipod mount under the muzzle.

The modified variant, called G11K2, was tested in 1989, scoring at least 50% better combat accuracy when compared to G3 rifle. Initial batch of some 1000 G11K2s was received by Bundeswehr in 1990 or so, but due to some reasons the whole programme was cancelled by German Government. Main reasons of this cancellation were, in my opinion, the lack of fundings after the re-union of the West and East Germanies, and the general NATO policy for unification of the ammunition and even magazines for the assault rifles.

The slightly modified G11 was also tested in the USA under the ACR (Advanced Cobat Rifle) programme, in 1990. The ACR programme was not intended to result in adoption of the new rifle for the US Army, just to test new technologies and designs, and the G11 proved itself as a very accurate, comfortable to handle and fire, and reliable weapon.

And a little Video