Re: Whats the most accurate 5.56 barrel for a 18" SPR
ever mk12 ever issued to the military regardless of branch has a douglas blank/compass lake turned 18" stainless 1-7(ish) twist barrel. when they say 1-7 it could actually be 1-6.5 to 1-7.5 twist and still be considered 1-7.
all the mk12's have 18" barrels PERIOD. not 17" but 18". the only exception is on this SOF custom ordered thru pri. heres an actual mk12 mod0, jihad stopping, taliban dropping upper. note the gen 1 tube, straight top rail with two picatinny slots up front, and wheeled front sight. all of these are hard to find and no longer produced.
the barrel fulton armory lists as navy contract overrun is actually a douglas blank with a 1-7.7 twist which is now the standard for the mk12, as to better stabilize the 62gr bullets (which it wasn't designed to do but in a pinch) as well as the 77's. i have one of the their contract barrels and before i bought it, i spoke with the gentlemen at fulton who put me on to the actual supplier so i could get some of my questions answered.
the closest to actual combat issued mk12 uppers are built by high caliber sales. they have been involved with the mk12/spr throughout and build the most accurate dependable uppers available to civilians.
i have a few mk12 mod0's and I've found different builders do different things better. i own one built by pri, one adco, two high caliber built uppers and two i assembled myself from parts.
pri is good, made with douglas/cle barrel and mil spec components 9/10
adco is good too but uses a white oak barrel,sub moa but i prefer douglas 8.5/10
high caliber uses only douglas barrels, colt uppers, lmt full auto carriers, just like the military does 10/10
one assembled by me with fulton navy barrel and rainier arms upper/bolt carrier, great with 68-75gr bullets 9/10
other assembled by me with douglas/cle barrel, colt upper and lmt fa bolt group, and original pri wheeled sight, my favorite 10/10
I'm not saying that i know everything there is to know about mk12's, I'm just saying i did a lot of homework on the mod0 and I've tested all of mine on the bench and in the field and this is what I've found to be the facts. any 223 rifle that can hit a man's sized head (8" round) at ranges greater than 700 yards with 10/10 shots is accurate in my book. all of the above listed uppers have done this, some with more consistency than others.