Kalashnikov Media has recently published an article about one of the Soviet experimental caseless rifles. Just like in other countries where the caseless ammunition was developed, the goal was to get rid of the case in order to have a much more compact and lightweight ammunition which would in its turn result in more compact and light weapons, too.
In the ’60s and ’70s, various design bureaus of Soviet Union were working on this concept. The rifle shown in the images of this article was made in IzhMash. The external layout and controls are similar to the AK rifles. However, the internal parts are quite different because the rifle was designed to shoot caseless ammunition.
This rifle is gas operated. Its firing pin doubles as a gas piston. Once the caseless cartridge is fired, the gasses directly act on the bolt face because there is no metallic cartridge to contain them. The designers of this rifle used that to power the operating mechanism of the rifle. The gasses push the firing pin into the bolt and it works like a piston pushing the bolt carrier back. The latter rotates the bolt unlocking and cycling the action.
Ultimately, all these caseless ammunition projects were halted in all the countries pretty much for same reasons. Compared to cased ammunition, caseless cartridges are more fragile, less resistant to harsh environmental conditions and rough handling. Caseless ammunition is also more sensitive to hot chambers and prone to cook-off much earlier than the cased ammunition. There are also some caseless weapon design challenges such as the need to reliably seal the chamber, extract the unfired ammunition etc.
Unfortunately, there are no surviving samples or photos of the ammunition that the ABP M-01 rifle was chambered in.
“Экспериментальный безгильзовый автоматомат”. (2018, March 23). Kalashnikov Media. Retrieved from: https://kalashnikov.media/news/4522202
All images from www.kalashnikov.media