davidsotactical asked: quick question so i just got my spr but wanna build a new upper basically i was wondering if i could get a 14.5" barrel custom made with a rifle length gas system because I love the rifle length gas system and a full auto bcg in my spr right now it has almost no upward recoil impulse and it is really SLOW if that makes sense its really weak and I have read this is due to the medium contour barrel, rifle length gas system and full auto bcg would it be viable to get the barrel made?
It won’t work, or it will short stroke. You won’t have enough dwell time. The gas tube only gets gas once the bullet passes the gas port, until the bullet leaves the muzzle. You need a certain amount of dwell time to reliably cycle the action. Check out some dissipator uppers though. Typically a mid or carbine gas 16” bbl. with the front sight irons pushed out to the end for a longer sight radius. A 14.5” bbl is designed for a carbine length system and an H buffer.