I'm having some trouble with my M&P 40 Magazines

[thebutcher]

I just picked up a VTAC M&P 40 and I'm new to the platform. I'm trying to get a feel for the pistol's functionality before depending on it.

What I'm experiencing is with the slide locked back, the magazine will not drop at all when fully loaded. They (2 of them) start having problems dropping after loaded with five rounds. Both of my 9mm magazines drop free without issue no matter how many rounds are loaded. All of them drop free without issue when they are empty. Anyone else notice this also? Does loading the 40 magazines cause that much expansion of the tube or could they just be defective? I realize not to rely on them dropping free in any situation but it just seems odd to me that they don't budge even with the added weight.

Another thing I've noticed is that you can't chamber a round by hand. If it doesn't load from a mag the extractor just beats the hell out of the casing and the slide doesn't fully close. Is that normal? (this test was not done with live ammo)

Thanks

[Palmguy]

Don't load/chamber the gun by hand...always load from a mag.

What you've experienced is normal.

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[Dos Cylindros]

As far as the mag not dropping free with a loaded mag, I don't know the answer. I would wager they are bulging and thus not willing to drop free. The early generation glocks were this way by design, but I have never seen or heard of it with metal mags like the M&P mags.

As far as loading the chamber by hand goes, you should not be doing that. The gun was designed to feed from the magazine, and dropping the slide on a live round is called "bubba loading" for a reason. It is not good for the extractor and shows poor weapon manipulation skills. The only place this type of loading is actually done is in the movies.

[Nephrology]

Definitely don't load rounds into the chamber by hand. If it is a magazine fed pistol, feed it from a magazine.

[thebutcher]

I'm starting to get the picture. lol

I was looking at it more along the lines that if the magazine is lost or fails then the pistol is functionally useless.

Thanks for the info and quick responses.

[Magsz]

Is the top round in the mag catching on your feed ramp?

If you shake the pistol slightly will the magazine drop free?

Are you depressing the mag catch fully? Yes, i know that one sounds stupid but ive got to ask.

[thebutcher]

Is the top round in the mag catching on your feed ramp? No

If you shake the pistol slightly will the magazine drop free? No, you really need to thrust down followed by an abrupt stop for it to drop.

Are you depressing the mag catch fully? Yes

There is quite a bit of friction in the mag well so it's not really catching on anything. Just the resistance of the polymer. When the mag is empty there is no resistance at all.

[Bubba FAL]

As others have mentioned, don't feed by hand, the M&P40s have a pretty robust extractor spring and it takes a lot of force to overcome it if feeding by hand - not good for the mechanics.

As to the other problem, I haven't experienced this with either of my 40s with 10 different mags. They all drop free regardless of the number of rounds in them. Could there be a bit of polymer flash inside the magwell that catches on a full mag?

The only issue I have experienced with M&P40 mags is a slightly annoying rattle if the mags are loaded with more than 10 rds. Makes it sound "cheap" IMO.

[thebutcher]

I only tested hand feeding it once with a dummy round to see if it could be done.

I've made sure the well is smooth and without obstruction. It's only a problem when the slide is locked back so I guess it's not the big of a deal. The mags themselves just seem to be expanding a little when loaded. I'll just have S&W take a look at them.

My PX4 storm and the M&P mags rattle like that when fully loaded.

Thanks for all the help guys.