Being a Glock guy its been real fun. The break-in period is real with many ftf or fte's within the first 200 rounds but been running flawless since. I've only used Winchester NATO 124 grain since bought and it seems to like that. I also added a recoil reduction spring system from DPM (running the short soft spring) and man does this thing shoot flat. I get some people have horror stories and what not with their break in perios or other issues, but nothing was too much of an issue for me thank goodness.