True enough - it does seem we have missed out on one or two follow-up reports. Guns that had troubles seemingly and went back. Harry - I do also sure hope your returned Pup will be well behaved.
I'd like to think that all that was wrong was righted with returned guns - if in fact the guns had faults themselves.
Re the springs in mags - to scarfe my pic from the site! - yes I do believe improper fitting of spring
could prejudice function. Notice how the spring in the correct position will exert a force to assist follower to stay tipped up at front. Put spring in 180º about and I suspect the presentation of a fresh round
could be impaired - may not take much but if that round is not exactly ''mated'' with feedlips for angle, well - not as ideal maybe. Certainly reliability could be prejudiced I think.
Look at it another way - if spring force on follower is not normal to axis of mag body - then we could see an increase in friction, between follower and inner walls - not much perhaps but possibly enough to reduce feed pressure.
Hmmm - pic not showing yet - wonder why!