I need a complete bolt carrier assembly for a non-LEO, non-combat upper, so are all these $100-$150 units by RRA and DS Arms, etc "good enough"? The gun probably won't see 1,000 rounds in a year, just a dedicated plinker. I know to look to see if they're staked properly, but what else, if anything, is critical? And my gun's a .223, so are all assemblies compatible or are some 5.56 only? I appreciate you educating a hobbyist like myself.