OK, here's the range test: Major problems, FTF, jams, mag will not stay lock = Problems solved after.
First round, jammed, took one jammed 15 minutes to get out with tools. FTF on a lot, mag just will pop out and when it did stay in the second round will not fire because it's FTF again.
I finally figured it out, it can't do 6+1. It's always a habit to chamber one and add another round to the mag like I've always done it. That's where all my problems happened. I use the flush mag in the pistol so the second mag, extension will not have the problems unless I do the same to it.
This pistol is so small, it just won't do a +1 in the chamber. I can't seeing the mag spring loosen up because it's already nice and loose. Maybe in a few months, 6 range test but I doubt it..
Test with Remington 115 fmj and it's jhp. Close to 200 rounds if not slightly over. This solved my mag from popping out and FTF and jams, I hope it fixes yours. My next will be to see if it'll take other than Remingtons that DB used to test my gun. Perhaps those Sig that's made for short barrels that works fine on Glock43 which takes everything. Good luck guys!