07-20-2020, 08:56 PM
Not all bolt carrier groups are made the same. I have many different types of BCG from back to the 70's. I pin gauge all of them, test the straightness of the gas keys, and check the finish with a bore scope.. Four of my favorite were quite cheep when purchased many years ago. The machining, internal finish were perfect. That said, I use only BCM BCG's in all of my new builds. BCM has been very consistent with their manufacturing. JP is top of the line and is the Cadillac of AR manufactured products.. I have an older Olympic bolt carrier that had the gas key channel milled crooked..If you are concerned with the YFS fastners, then it is quite easy to replace the screws with a new BCM key and fastners...https://bravocompanyusa.com/bcm-gas-key-with-fasteners/ You can seal around the gas key port with Permatex aviation form a gasket https://www.permatex.com/products/gasket...nt-liquid/ or use green loctite. Torgue to 58-60 inch lbs...