Ooof. How to spend a year. LoL Very nice job, but I will try to avoid projects that intense. I think fabricating the occasional replacement bolt or pin (if I can't find them pre-made at Numrich or Brownell is about as far as I want to go in that direction. He is quite right about the interplay of breech, magazine lips, feed ramp angles, slide mass, striker position and a half dozen other variables all being very critical in a reliable semi (or full) auto firearm. Giving him lots of credit as the .22 rim fire is considered one of the most difficult to get that balance just right on. It becomes much easier to get that balance right with FMJ straight rim cases like .380, 9mm, 40S&W, etc. BTW, I love my Ruger Mk I standard and never saw a need for something to replace it as a rabbit/groundhog pistol.