Drum:
First, welcome to the Forum.
Without knowing which bullet in the magazine tends to hang up on the feed ramp (first, last, or something in between), it all sounds like a magazine problem -- possibly a spring that is a bit too aggressive. I agree with the suggestion of "de-stressing" the spring a bit. Also, I'm one of the apparent few around here who use Golden Sabers in my R9. I've never had a problem with them.
Suggestions: Clean and lube the R9 (I recommend FrogLube or Ballistol with a touch of SuperLube on the rails) and give it another range session with Golden Sabers, downloading the mag each time by one round and giving the piece time to cool some between strings of fire.
Good luck. I've been carrying my R9 for over 8 years now EDC. Admittedly, I'm obsessive/compulsive about keeping it clean and lubed, but it has shown no vices.