I used a Seekins I had laying around that I didn’t have plans for. If I was buying one, I would probably get an SLR. I like the no set screw design.
You definitely want an adjustable Gas Block, as the 308 AR’s can be over gassed easily, especially with the mid length gas system.
I have a 16” Mega 308 barrel. When I was shopping for BCG’s I read that Mega recommends Lantac and RCA (Rubber City Armory). The RCA was out of stock and I felt the lantac was a little to pricey. If money is not an issue, JP would be the way to go.
Others that I looked at were:
Rainier Arms...