Russian weapons are what they are. Robust weapons with very violent operating systems that will slam rusty, pitted ammo into battery. Since they will slam almost anything into battery, they will cycle darn near anything. They were made to mass produce very cheaply, and be very reliable in the hands of those with little to no training.
Try taking the bullet guide out of your AK. I bet money that the round hitting the breach face instead of sliding into the chamber will unseat every round and jam the projectile into the casing. Actually, don't do that, it's not all that safe
. Also, the gas system lets A LOT of gas through, basically able to pull damn near any ammo out of the chamber. Hell, you could pit the chamber and fire brass ammo, and I bet it would still rip the rim off of the casing if it didn't extract case in full.
With all that being said, an AK is a darn good weapon for the price... er well it was a good weapon for the price. These days... not so much. It is not indestructible, It is not rust proof (nor are most finishes on AKs of any comparable quality to most western weapons), and it will not survive being run over by a humvee unless you run over 2 inches of the muzzle and nothing else. They're decent rifles that fit in with Russian military doctrine. With that said, I'll take our version of the assualt rifle any day of the week if I have to go to war.