*This ONLY pertains to lowers that have tight tolerances and this issue, but alao reflects on 556 M3 Pmag "model variations" even of the same year of production, that do not have the right fit!*

So My buddy called me after getting his first AR.

His Older Gen 2 and new Gen 3 Pmag would Not drop free and were tight to insert but rubbed inward, I looked and when inserting it, I knew where to the issue was instantly, I just didn't realize what my findings would be when comparing to others!

His magwell is indeed tighter than standard spec, BUT, upon grabbing some other Pmag variations, Magpul has some odd inconsistencies here aswell!

I compared 4 different styles Pmags stamped as 2020 production (and 2 older ones) and it appears that Magpul doesn't create all of their mags equally!!!

I compared a Gen 3 "Windowed" and "40rd" Pmag to his solid polymer (Standard) M3 Pmag, and his has a thick ramp "above" the mag catch slot, which seems to be the area that's binding in his magwell being it adds more width to the mag's side, leaving it tight when trying to clear the bottom lip of the magwell when inserting, and not able to drop free...

Yet on the Gen 3 "Window" & "40rd" version, that upper ramped area seems to be trimmed down MUCH lower (only a tad bit of it even exists) and it slips right in and drops OUT perfectly, as a Pmag in a proper spec magwell does.

Seems the older Gen 2's have that top ramp also yet not as thick as the standard Gen 3s, yet it's barely there on Windowed M3 30s and 40s, and non existent on the new Gen 2 models!

I know your thinking "They can be sanded" but if new from the package, kinda sucks unless their is a good reason for this "One Model" to be thicker.

In summary,
Wondering why the solid polymer Gen 3s have this area so much thicker/pronounced as if a reinforcement?

If it's to aid/reinforce, why do the Windowed 30s, 40s, and new Gen 2s basically (or fully) lack it all together?

Dupe

Just an observation/ remedy for many who have threads or youtube videos about sanding that upper ridge/tab.

Just figured I would post it incase anyone has issues with Pmags fitting their lower, and letting them/you know the models that bypass the issue.

Sorry so long winded but just wanted to explain the differences in depth.