Morning RedmistofIdaho

While I haven't broken the hammer pin on my S&W 15-22 (but it has a larger diameter .160" hammer pin I made from drill stock as the original .154" was a bit loose in the lower's pin holes).

I have broken 2 hammer pins in my RRA M-4 lower when used with my CMMG dedicated 22 upper. In talking to RRA they said that when their lower is used on a .22 upper that happens frequently. They seemed to break around the 8,000-10,000 round time period.