Several years back, I picked up two sets of Armalite-pattern 80% lowers, with uppers to match. Seller (A well-known internet vendor) listed them as Diamondback Arms receivers.
Fast-forward to last night: I'm machining them and I notice that the selector detent hole (which was already machined when I got them) is 0.140" to the rear of where every print I found said it should be. I see this going three ways.
1. The entire FCG is moved aft 0.140"
2. The selector only is moved aft 0.140", and the tail on the trigger is long enough it still works.
3. The detent hole is in the wrong spot.
In the haze of already being set up and rearing to go (and not wanting to lose said set-up when day shift comes in the next day), I assumed #3, because I've had both AR15 and AR9 80%'s with that hole not in the correct location, just never off by that much.
When I install the grip....the hole was in the right place to match the hole in the grip. Shit.
So, does anybody know if either 1 or 2 is correct? Right now, my pocket and fcg holes are machined 'to print' which puts them in the same locations as an AR15 relative to the mag release and bolt catch features (at least, I think so). If they ARE actually 0.140" too far forward, will the hammer still hit the firing pin at correct-enough angle to fire and not break firing pins?
I don't have any barrels or bcg's yet, and never expected a problem like this with AR10's. Thanks for all advice.