PMAG vs. S&W M&P 15 stock magazine

[eswrite]

Yesterday I had another misfeed issue, this time with a PMAG magazine. After that, everything worked fine. But when I went home, I decided to take a closer look and this popped out: the stock magazine that came with my M&P 15 Sport II has perfectly square slot at the back of the magazine, whereas the PMAG's is slanted (ditto for my Hexmags, not shown here).



Question is: should I dare to square off that slot? Or leave as is? The bottom edge of the slot on the stock mag measures a little over 10mm (~10.5), whereas the PMAG measures a little under 10mm. Could that be making the difference?

ETA: notice the tiny thin triangles toward the bottom of the PMAG slot, almost like they're intended to be shaved off...

[comifornia:(]

You could square it up a little bit. I think the Tavor recommended it be squared off or use a specific later gen pmag.

[17+1]

[trackhazard]

S&W M&P here. No problems with either pmag G3, factory S&W mags (which are made by ASC or the aftermarket stainless ASC mags I bought.

I took a look at my pmags and they don't have nearly as much mold flash on them as yours (there is a little lip I can feel with my fingernail but thats about it).

[hitdank]

Take your bolt out and run it through the top of magazine.

[mofo1111]

Is your rifle new? Is it clean? Sorry to ask but...
I had a brand new pistol caliber carbine that was mis feeding new. Part of it was the ammo having a short COAL. Next range trip, I had the bolt lubed up real good. Being that it was brand new, everything was tight. The well lubed gun ran like a champ after that. Now it doesn't need as much oil or grease now and feels super slick. I never had issues with P-mags. Just a thought...

[eswrite]

Is your rifle new? Is it clean? Sorry to ask but...
I had a brand new pistol caliber carbine that was mis feeding new. Part of it was the ammo having a short COAL. Next range trip, I had the bolt lubed up real good. Being that it was brand new, everything was tight. The well lubed gun ran like a champ after that. Now it doesn't need as much oil or grease now and feels super slick. I never had issues with P-mags. Just a thought...

Yeah, it's brand new, but I stripped, wiped, and lubed it before the first outing.

[SISKIN]

Usually with all my new rifles i clean them lube them and will dry cycle for about 1/2 hr while watching TV . With different Mags.

[wild_weasel]

I bought each of my children an MP-15 Sport and have had no issues using 10 round PMags in either.

VR,
George

[SVT-40]

Shoot three or four hundred rounds then check back about any issues. Use a liberal amount of oil too during break in.

Until then don't get the vapors over an occasional issue.

[deephouse]

[kcheung2]

I think you might be on to something.

OP: When you load the mag, are you pushing the rounds all the way backwards such that the nose doesn't get hung up? Ya know in those war movies how the soldiers tap the mags against their helmet before they go into battle? Part of that is to ensure that the rounds are fully pushed back. To keep the same strength, Pmags have to be thicker than their steel counterparts, which means the internal dimensions are just a little bit smaller & the projectile is just a little bit more likely to catch on something unless the cartridge is pushed all the way back.

[deephouse]

I think you might be on to something.



OP: When you load the mag, are you pushing the rounds all the way backwards such that the nose doesn't get hung up? Ya know in those war movies how the soldiers tap the mags against their helmet before they go into battle? Part of that is to ensure that the rounds are fully pushed back. To keep the same strength, Pmags have to be thicker than their steel counterparts, which means the internal dimensions are just a little bit smaller & the projectile is just a little bit more likely to catch on something unless the cartridge is pushed all the way back.

[triggs75]

OP you stated “this time with a PMAG”. Does that mean you had a miss feed with a different mag first? Have you tried another pmag? Might just have a bad mag