Also a "hello" to Luis, and I will tell you
right now that I'm quite envious of your fine pistol!
I am curious about your charge weight...
Is it 3.7 grains? That seems a but low to me as I have used a stiffer charge under commercially cast 125gr LRN bullets in 9mm. I suppose I am simply curious about how you worked to that charge weight and if you have chronographed that load and measured it's velocity.
Perhaps I should try that myself and see if it operates my 9mm handguns.
I do agree with you that I have not had good luck with Universal powder in .38 Special loads and agree that it prefers to be compressed to work well, and that simply isn't going to happen in .38 Special brass.
My "go to" 9mm load for 124gr plated or jacketed 9mm using Hodgdon Universal is 4.3 grains. It's a terrific load and I've made many thousands of them.