Receiver hammer and trigger pin holes vary between .154 and .1575, so we offer pins in .154, .155, .156 and .157 sizes to fit any receiver as well as our premium STBATm - STAINLESS TRIGGER & BUSHING ASSEMBLY for AR15/M16.
If you build multiple AR15 and need a variety of pin sizes, we offer a complete selection of pins in each size in our HAMMER & RIGGER RECEIVER PIN KIT which includes TWO PINS OF EACH SIZE.
This product can expose you to chemicals including lead, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov. 
