Originally Posted by
Jim D
Well, I literally just spent the last two weekends teaching our Armorers Course to students, and wrote most of the slides we use on dwell time and port sizing…
I don’t know why you seem to think that telling someone that they’ve made a mistake that can not be reliably corrected is telling them to piss off. Part of being trusted in your field is knowing when to tell people no to a bad idea.
It’s highly unlikely that you’ll find a way to make this reduced length barrel reliable now, and simply replacing the barrel and gas block with known quantity items is likely the most cost effective, time effective, and reliable resolution to your “friends” woes. If 5.56mm NATO carbine gas length barrels were viable below 10.3”, I think you’d be seeing at least a couple of them floating around. That you don’t is a clue. You’ll be in experimental territory trying to force this thing to run, with what will likely be an extremely narrow window of circumstances under which it’ll actually work.
Alternatively you could fix this problem tomorrow and give this dude a highly reliable upper again… with a 10.3” barrel setup that’s already been proven to work in every corner of the world.