What's great about the AR platform is that it us customizable for each person's preference. I would stick with known companies....BCM, Larue, JP, Spikes, Daniel defense, Midwest Industries....there are others but this is a good place to start.
Sounds more like a detonation issue than head spacing.
Thanks again to everyones input.
I generally just use Midway. I just put together a wicked awesome carbine for $400, but I had a barrel, gas block, and stock on hand. The lower was a bit pricey for mil-spec, but it was one of those custom-rollmarked BoomerShooter lowers.
