The instructions for the RRA 2 Stage Trigger require that you use the national match hammer & trigger pins, which have a diameter of .156 "for the system to work.
1. Why does RRA require an oversize hammer & trigger pin with its 2 stage trigger?
2. Will using standard .154 diameter pins really not work with it?
3. Since a standard pin has a diameter of .154, will the .156 pins stretch the hammer/trigger pin holes in the receiver to adversely affect later using a standard hammer & trigger and .154 pins? Once you use .156 pins, do you always have to use those pins instead of .154 pins?
4. What is the purpose of the oversize (.156 diameter) pins? Is the pin rotating, a bad feature?
I've used the .154" pin in a new (at the time) RRA lower because the .156" pins didn't want to go in.
I used the .156" pins in my Oly lower that has around 2000rds on it and they slipped right in.
Some people take some emery cloth and they lightly sand the finish down on the .156" pins and they then go in.
I've had no problems out of them.
RRA wants those size pins used because of the precise 'tighter' tolerances needed to maintain the stability of their trigger system...
.002" per pin difference means a total of +- .004" difference between the trigger and hammer...
Having a total of +-.004" difference when using .154" pins can cause the RRA 2-stage trigger to have to much, to little or no second stage at all... Its all about precision