MR308

What do you mean by “not long enough”? As in go rifle length gas system? And it is commonly 1:10 in most barrels, yes. Originally it was 1:11.25, and I was asking 1:9 for bullet stability reasons out of the shorter barrel how are your groupings at 14.5” with a 1:10? - And how are they at range?

Well, I hate to be the guy that digs up old posts like this, but I’ve got a new kind of conundrum. So I’m building a 14.5” .308 AR10. I’m having mcGowens make a barrel for it but I’m trying to find the best set up. The barrel will be pinned and welded with a Gamma VG6 and I have been planning on using a mid length gas system. I’ve heard back and forth opinions about twist rate and I was initially set on a 1:9 for added flight stability but I have people tell me that may be “too fast”. The other thing I’ve been trying to figure out is if I can cram a rifle length gas system on a 14.5 inch barrel. Based on what I’m reading here that’s a no due to not enough dwell time, but I wanted to figure out if I could. I don’t know the numbers to crunch but I was looking for someone who did. My main thought process for this was that in a 14.5 the bullet would leave the barrel before all the powder in the casing has burned (at least that’s what I’ve read). So I assume that having a longer gas system would allow more pressure for a longer duration behind the bullet, this increasing muzzle velocity. Of course I don’t know a lot about ballistics as this is the first AR I’ve built and I’ve never reloaded, so this is all theoretical for me. Thanks for the help in advance!