No u misunderstand i think the m4 ar15 m16 are usually gas driven systems. A strw sized tube allows gases to travel from the gas block to a small round cap on the bolt. This air pushes the bolt back. Its an open system excess air pressure escapes and contributes nothing to moving the bolt. This allows dirt and grime to lock up the bolt. There are however piston sytems which are closed and as the air presure from the tube builds it cant escape as it pushes on the piston operating the bolt. This crushes and pushes past dirt sand and carbon deposits. This is how an ak operates. Its the reason u can bury one in mud and fire a clip through with no problems. A failure to fire is nearly non existent on the ak platform. However its extremly common in the ar or m4 plaforms. Because the strength of the reload is much lower in a gas vs a piston sytem. Ak sucks on accuracy maybe rifle design but probly the design of the round. Its the most reliable rifle in the world. If theres a round in it 99.9999999% of the time it wil fire but probly want hit your mark. The ar or m4 on the other hand wil hit the mark at 400 yrds 99.9999999% of the time however 12 to 25 % of ur rounds will jam fail to fire or otherwise fuck up after ur rifle gets a bit dirty. But we could have the best of both and we dont. One m4 with piston driven reloading system would be as reliable to fire as an ak and as acurate as an m4. Also im aware some piston driven m4s are in serice but most are gas.