203d Military Intelligence Battalion, US Army Operator's Manual for the AK-47 Assault Rifle (August 2019)
“ Drilled rounds are designed for training in loading and firing. On the body or the cartridge case there are longitudinal grooves, and on the cartridge case mouth there are marks from the clamping device. The primer is pierced. There is no propellant in the cartridge case. Blank cartridges are designed for simulating fire and are used in tactical exercises. There is no bullet in the blank cartridges. The mouth is sealed by a star (rosette) crimp. It is dangerous to stand closer than 10 meters away from the muzzle face when blank cartridges are being fired. ”
