Have 2 dedicated uppers, first one is a 16" 1st generation Nordic, zero problems. Just built an upper using the CMMG Bravo/Evo stainless group with a 1:16" Lothar Walther dedicated barrel, Odin O2 Lite 12.5" handguard, Anderson upper receiver, Primary Arms Rimfire 1-6x ACSS scope. The...