EFrench-
It is a learning curve of course. I wish I could help you more with the XDm. Sounds like your getting good case support with the barrel. Yea, when I want to shoot long range (with rifle) I have to place my crony in the sun sometimes. It is problematic.
Work with the heavier springs when you get them. Use the minimum spring rate that works. Too heavy and you run into other problems. Your mag spring should work, but the return slide battering can become a problem over time.
