Originally Posted by
montrala
Overheating... no (unles you try to use DI AR15 as volume fire). But heat stress from cycles of heating to high temp and cooling down is. It gradually destroys internal structure of alloy reducing it's strength. It takes time and in range used semi-autos usually do not show at all, but in hard driven professional tools it can be a problem. Especially with shorter gas systems (carbine and shorter), when amount of heat transferred into bolt is much higher than originally designed by Stoner in M16 (actually if not chase for shorter barrel, adding pistons to AR15 design would never be needed).