From what I have seen a tight magazine is normally a magazine issue, not a gun issue. If you remove 1-2 rounds from the mag, does it still feel the same way?
I would pick up a new mag.
EDC's: G21 Gen 3/Trijicons/TLR1 - XDS 45 Backup
"...to disarm the people - that was the best and most effectual way to enslave them." - George Mason