I just posted this for someone else about a week ago. I put RRA 2-stage triggers in 2 Bushmasters. Miked the pins, stock pins were .154", RRA pins are .156". A 5/32" drill bit is .156", so I carefully used the drill bit to ream the receiver holes. Took great care to make sure the drill went straight through and didn't wobble. I used to be a machinist, so I have a little more confidence with this type of thing than the average person. Worked great, nice tight push fit on the pins.
I would not use the RRA trigger and hammer with the .154" pins. I'm sure the parts were designed to work with the larger pins. Extra clearance on the pivot pins could mess up the trigger action.
Kind of irritating that RRA doesn't mention this issue in the directions that come with the 2-stage triggers. I'm very pleased with the end result though.