Trigger and Hammer Pin Holes

AR/M4 AR Technical Discussion
1

I am building a higher end AR15 for precision target use, and wondered how important snug or tight fitting trigger and hammer pin holes are. I have two receivers, and the hole diameters are such, where one is a loose fit (pin falls through under own weight), while the other is much tighter.

The pins are under substantial pressure, and probably would not turn in the receiver even if loose, but would loose clearances cause any trigger performance issues, such as inconsistent pull or feel? Anyone had experience with that?

I am using a Geissele trigger. Geissele does not recommend using KNS pins, so oversize pins are out. Geissele pins have grooves in different places than normal trigger pins. Even Geissele’s oversize pins are loose in the one receiver.

Thanks.

  • Phil
2

The pins are not held in by press fit into the holes. The trigger pin is retained by the hammer spring and the hammer pin is retained by the J spring in the hammer. As long as the holds are not egged out or grossly over-sized, you should be okay.