I don't think he's built the guns yet; if he has AGB's a light(er), assuming not Ti weight, BCG's will work fine with carbine or H1 buffers & a standard or enhanced spring if he understands how to set up the rifle.
Not sure he really understands all that he knows by the questions he's asking.
Might be wrong...............
MM
Probably not .
First outing with lite weight BC.
