Roller,
I am posting my reply to your email here.
I thought about relieving the tip of the firing pin. I was going to use a counter sink. I did not try this. I went on the non rotating 4 mm square shaft as I wanted to shape the pin as a wedge as suggested by many others.
I now use my tool and cutter grinder to shape the pins. Five degrees on the end and ten degrees on the sides. A rake of two and a half degrees on the sides, top to bottom. I used Roller\'s .025 measurement at the top of the pin. All the pins are now uniform. This seems to work well in my tests.
I also found that the pin location was questionable. So was my skill at indicating a dividing head. I had found that the pins did not hit at the same place. I thought it was due to the called out measurement, the dividing head set up, and the bolt carrier.
I found that by following the instructions and machining the bolt holes by drilling they will never come out in the correct place. I changed my machining procedure and used a long end mill to bore the holes after drilling, then ream. I am thinking about a set up to use a boring bar or a gun drill to make these holes.
I am thinking about making the shaft one piece and making the carrier two pieces to see if this will help with the alignment.
