I know that on carbine/mid/rifle length gas systems, proper gas block alignment involves a 0.020” ish gap between the gas block on barrel shoulder to account for the lack of the handguard retaining cap with a free float rail.

I haven’t been able to find out of this should be the case with a pistol length gas system or if it should be pushed up to the shoulder due to the delta ring style handguard not being used on pistols.

Upper in question is a PSA 8.5” .300 Blackout. Barrel wasn’t dimpled and set screws were barely finger tight. I dimpled it, loctited, torqued, and staked them, but didn’t leave any gap.

So far it has run 100% with subs and supers, both suppressed and non with an H2 buffer, but I want it to be right. My concern wouldn’t be a relatively small gas port not being perfectly centered in a large gas block hole, but rather there being some sort of “lip” from it overhanging the port slightly and building up carbon deposits, clogging it over time.