It could just be the ammo I used, but I've had 3 malfunctions so far. 2 of them, the same type, so it could be the ammo, which was Remington UMC. Both times, the empty casing failed to eject and ended up being stuck inside with the bolt pressed against it...sideways. The other malfunction was the bolt failed to lock back. Never had this happen with the CZ mags and I couldn't replicate it.