.015 is a lot in the machining world.
I've been playing with the Macon Armory 45 acp upper for a while now. Let me say it is really fun! I worked up some hand loads, but I wasn't too satisfied with the results. I'm going to try some different bullets next time and if the results are better I'll give a more thorough report. Winchester whitebox and tulammo fmj work well
Right now the gun.doesn't like to feed truncated cone, flat nose hollow points (hornady 200 grain xtp), or swc bullets. Macon Armory is redesigning the feedramp on their HK USC mag adapter to fix this. However, it functions flawlessly with round nose fmj, round nose lead, and round nose flat point lead. These are the bullet profiles that the feddramps and chamber were designed around.
When I get more information and testing I will report in again.