Issues with Mec-Gar magazines for Glock

[u/Drasselll]

I've been struggling to make the last two rounds feed reliably in my Glock 17 gen 4 from my new Mec-Gar magazine, while my OEM gen 5 mags feed perfectly everytime. The last two rounds often don't get picked up by the slide, even thought the magazine seems to be perfectly seated.

I've talked about it to a friend who then let me test his own magazines with his Glock 34 gen 4, and they fed perfectly. But when I tried one of his in my Glock 17, it would do the exact same thing as mine.

This is confusing me because I thought that perhaps it would be a simple magazine problem, but now I've got the feeling that I'd need to check the gun itself possibly.

Here's what I tried so far:

-I tried cleaning the gun (duh)

-I tried 115gr, 124gr, 147gr JHP

-I tried surplus +p+ IVI ammo to check if more slide velocity did anything

-I compared my Mec-Gar with my OEM magazines at the range

-I tried using someone else's Mec-Gar magazines in my own Glock 17

What I didn't try yet:

-Trying my magazine in someone else's gun

-cleaning and lubricating the magazine with ceramic coating (although it doesn't have a very high round count)

-Changing my Glock's recoil spring with a brand new one (friend's advice)

-Testing if my support hand rubs against the slide sometimes

-removing my Magpul magwell (maybe it's contacting the mags)

-Revert my Gen 5 OEM mag release to the original Gen 4 one (not sure if that'll do anything)

If anyone has any experience or solutions to share, or just wants to tell me that I'm overthinking and perhaps should just stick to OEM magazines (like God intended), feel free to do it.

[u/hectop20]

If I'm understanding the issue correctly, it sounds like the spring isn't strong enough to feed those rounds up. Maybe take the two different mags apart and see if the springs are the same size.

[u/Drasselll → u/hectop20]

That's what I'm thinking. It would make sense that the magazine spring isn't pushing the rounds fast enough before the slide closes. I opened my mag, my friend's mag and one of my newer Gen5 OEM mags, they're all basically the same lenght ± 1/16". All mags have less than 200rnds through them except for my friend's.

The Mec Gar spring is a dual-rate design. The coils change shape about halfway though and become much thinner towards the follower's end.

I know that my Glock is pre-owned and I don't know how many rounds it had through before I got it just before the handgun freeze, but I know that I put already 2-3k rounds through it since and that I intend to put way more in the future. I think I'll try changing the recoild spring and see if it changes anything. Like my friend suggested, perhaps it's simply that my slide's velocity is too quick for the Mec-Gar mags.