Gunsmith who will make a relief cut on an AR Upper?

[Oscar77]

I'm sorry I should've been clearer.......................

Alot/Some of RR AR15 are conversions of the old COLT SP1 rifles............ but they are the so called "large pin" versions.
SO........................ unless you want to use the pin adapter............. you can still get the "large pin" uppers.
BUT........... they don't have the relief cut on the uppers, which if you don't have, will bind up the auto sear............
So either get the large pin upper modified or buy one purposely built.