[Frank]

First, you are correct in the variations in pistol and magazine dimensions. The magazine follower button diameter, the button slot length in relation to the magazine catch notch, spring force are among the potential problem areas.


Then there are differences in various ammunition.


I would select the magazine that seems to work the best, manually. Then, I can't remember who mentioned this, but I agree with it. Place one round in the magazine and fire it. If the magazine will hold open manually and the round fails to hold open, then the problem is probably the ammunition. Hope this helps.