MK 12 MOD Murph, SPR build revisit

[@henrychristopher9131]

I had a PSA 18'' barrel with the same last round hold open problem and put a KAK yellow color code buffer spring and 2.7 oz lite buffer and it fixed the problem. I have another AR 15 with a B. King firearms BKF 18'' 223 wylde 416r ss black nitride with ops 12 cuts for the collar for the can and the barrel likes AAC ammo 5.56 75 grain BTHP at 10.99 a box on sale and 11.99 at full price. Thats only 1.00 to 2.00 $$$ above 55 grain ball ammo. They also have a AAC ammo 77 grain OTP but my barrel likes the 75 grain more and consistent. Best group to date is .500 but will shoot .650 to .800 all day.

[@murphslaw1276]

That AAC load is super recent and I can’t wait to get my hands on it.

[@jbcustom3745]

what brand of collar are you using? Im building one also a Mod 1 clone and I can't seem to find the brake and collar that include the longer collar for the MK12 Mod 1 configuration. I got a Douglas 18 inch but if you want to save some $ and get a much better barrel then a BA I recommend Centurion Arms 18 inch SPR profile barrel. you can find them for about 425$

[@murphslaw1276]

I ordered that brake and collar direct from Ron Allen, Allen engineering. The original review has the story but the abridged version is I called him and he happened to be sitting down to make some and I ordered it on the spot.