Castle,
in the case of Luger mags, a stronger spring is usually better- you may try some lube in the magazine itself, sometimes they get really dirty and the follower doesn't want to move freely.
Ammo- Just a few months ago, I sold a well functioning .30 commercial to a board member(could have been the other board), worked 100% for me and the guy wanted a shooter.
Sent it to him and it would not function for him, no way no how- "same" Fiocchi ammo!
ONly difference was 600 or 800 miles.
Guy is a competition shooter, we discussed it, but it was not limp wristing.
I finallly sent him some of the box of .30 luger Fiocchi I was using.
Problem went away, 100% function again.
Difference in ammo- mine was RNJSP he was using ball, Fiocchi load both.
Fiocchi give the two loads, same bullet weight, one just soft point, two different velocity ratings-
you would think the 10 fps difference they give would be irrelevant, but it just means they are performing differently for some reason.
Since then, I have read on another related thread that Fiocchi has changed their loading in the last some years, so the ammo may be or likely is different lot to lot, or certainly ammo a couple years old to now.
Moral of the story- you problem sounds exactly the same- it is likely the Ammo!
