Do you keep the mags jammed for long periods of time, or do you shoot often enough to cycle through them? While deployed overseas we would keep bags of M4 mags loaded for our "speed balls". Over time the springs will become weak. And cause feeding problems. But those were gov issue mags not high quality HK or Magpull magazines

Good point, and I don't even keep my "ready ammo" mags topped off, let a lone stored ones!! Even when in the Army I'd keep 2 less than full. You never knew how old and/or misused the ones you were issued were. Smart money would depress and release springs several times and carefully eyeball overall condition before using.

When I was in the Reserves in the early '90s pretty much all the NCOs I knew bought 5 or 6 new mags. I even up gunned to a Glock 19 from my tried and true snub nosed .38 special for Desert Shield/Storm.

BTW a couple of years ago I found one of my original Series II Glock mags had spilt at the top. Just like Glock warned they might. Still fed fine and never a jam. But really had to tug on it to extract from pistol.

I think it was Vice that first told me this might happen. So I blame him!! Since everyone knows if you don't say it, it won't happen!!