I know this started out as a mag seating issue, and for that I would say change your mag release button if you haven't already.
You guys have been talking about extended base pads. Well, I have been using the new Arredondo base pads for about three weeks now and so far I am very impressed. I can put all 20 rnds in quite easily, the tubes don't swell so you can do a speed load without a problem, they come off for cleaning very easily but can not pop off when dropped. The plastic is very sturdy and won't break even when dropped on concrete. Give them a try!!!
Debbie