I have a 6mm Arc AR 20in Faxon Match Series Barrel - Heavy Fluted Contour, 1-7.5 twist, 416R Stainless Steel QPQ Nitride Finish, 5R hybrid button rifling - Nickle Teflon Extension - 100 round through the barrel.
I have a Superlative Arms Adjustable/Bleed Off Gas Block with gas tube to match.
I would actually like to sell this as a complete upper - Aero Precision receiver and handguard, Brownells BCG. But selling the parts separately is no big deal. I do recommend getting the gas block/tube with the barrel at least. The bleed off feature is amazing if you want to run suppressed.
I'll provide pricing depending on how much, if any, you are interested in. Thanks!