Wow, another 8.6 blackout victim of hype...I purchased the Faxon barrel in 8.6 early on out of curiosity, of the 3 twist. The totally worst barrel I've ever seen as far as rifling goes, it was dangerous to the borescope. Galling, torn pieces of metal hanging in the bore, torn from bore to land...it would appear the rifling button clearance and lubricant were not up to par. Pieces of metal and rust came out of the bore.. built a fixture to lapp it with carbide lapping compound, and a finish polish...it was smoother and I could actually see rifling... but with heavy reamer marks and torn out pieces metal off the bore, but better toward the end of the barrel. The first supersonic load from Faxon data damaged the magneto speed bayonet and the muzzle brake, as the 3 twist caused lead bullets to blow up as soon as they left the confines of the barrel. Their load data for 225 blew out primer ..check with others on this experiene ..So test without a muzzle device, or suppressor.
Played with it for along time. Conclusion it worked best with 300 gr SMK and 300 gr Berger at 1000 fps imr 4198, better than AA 1680 fairly accurate..and kinda fun.
Their bolt gun barrels were standard Remington thread the last I checked, 1.060 X 16 only those actions so threaded would work with this barrel nut arrangement.
Go to a pawn shop or buy a new 308 700 $465 for the whole complete rifle, take off the barrel, thread on the Faxon barrel, with a go gauge installed..tighten the barrel nut done....the Faxon isn't likely to be a tack driver...but my ugly barrel does pretty good with 300 gr match...a waste of good Berger bullets...but it's kinda fun, took along time to warm up this pig. Oh and you'll probably not have fun making brass. They all should be neckturned into the shoulder... without a metal lathe and collets it will be labor intensive. Best advice is, give the barrel to someone else, to play with...unless you insist! The 8.6 Blackout has too much capacity for subs and too little for supers...and the 3 twist is unnecessary, and a bad idea...where an 8 or 7 twist would be more versatile, and do the stability job.... a 3 twist ain't gonna help ya kill anything more enthusiastically, but limit its usefulness...my experience and opinion with this thing called the 8.6 Blackout.