So if I understand correctly, you have removed the required spacer to relieve the spring tension to get the gun to cycle and REMOVED THE MECHANICAL STOP THAT PROTECTS THE GUN AND YOU!

The Nato ammo you are trying to run is lower pressure thatn the gun is gassed for! The guns are gassed for US made Brass Hunting and match ammo at full pressures. They do not like the lower pressure rounds. If thet bolt overtravels with normal pressure rounds, bad things can happen! You are talking the bolt moving back two inches farther than it is supposed to!

That buffer had a hard rubber stop on it for a reason, a mechanical stop!

You are running stock spring and buffer, correct? Longer tube requires spacer!

Now if you want the gun to run lower pressure ammo, you will likely have to take the gas port from the stock .068 diameter to .075 to run cheap **** reliably.

Now take that as you wish before you break something!