Took me 2 years to source all parts using my mr223 as a reference point. No Brownells junk on this. Its All Nefarious, hk, hoss. Nefarious adjustable gas block, hk barrel, a5 quad rail, hk a5 lower parts full ambi lower. Geissele smr handguard, geiselle trigger. No expense spared on this. See other listings for trade interest mainly loaded nrch scars But will sell.