[GoldenSaber]

I have a full size M&P 40. One of the magazines is driving me nuts with ammo rattle. :blink: I load it and about where the 7 / 8 hole is on the mag you can literally see the cartridge moving slightly forward and back. I have inspected and cleaned the mag inside and out. There is no visible indicator of any damage or non-uniformity that I can see. I have also put different ammo in the mag and same place... same rattle. I know it sounds trivial but in a concealed carry environment I am not interested in having a rattle. I assume that there must be a slight gap or misshape to the mag in that area allowing for this?

Thoughts, suggestions, fixes?

 

[Rugergirl]

Have you tried changing the spring? It seems possible that it may have lost some tension, allowing the rounds to move around a bit?

 

[GoldenSaber]

Have you tried changing the spring? It seems possible that it may have lost some tension, allowing the rounds to move around a bit?

The mag is only about 2 months old. Wouldn't think it would need to be replaced yet but anything is possible.

 

[Jackle1886]

Call SW customer service, they should take care of ya.

 

[barracudamagoo]

Is it just at the 7/8 hole? I know mine makes a little rattle when it is loaded with an odd number of rounds (1,3,5,7,9,11, etc.). If I have an even number of rounds there is no rattle. I presume it is because of the double stacking, but I have never had any issues with it; the gun fires fine. It sounds like you may have a different problem though.

 

[Rugergirl]

The mag is only about 2 months old. Wouldn't think it would need to be replaced yet but anything is possible.

It kinda depends, do you shoot it frequently or load and unload the mag often?
Constant pressure on a spring (or the lack of) doesn't weaken the spring as much as compressing and decompressing the spring does.

 

[JAT40]

I believe these mags are slightly over sized to accommodate all brands & types of ammo. Do you top off the mag or not? Try both ways. Also do you seat the ammo in the mag with a swift palm slap? Seat from the bottom and back of the mag. There might be a shim available, have not checked, worth looking into. Beats buying more mags to find some that don't rattle. Good luck.

 

[Tangle]

This is not uncommon on stagger stacked mags. I've had that with my Glock mags, and seem like some others. It never seems to cause a problem though.

 

[Der Alte]

If it is the spring, remember that all things made by man are apt to fail at some inopportune moment. Years ago I bought a new vehicle, drove home and the next day the battery had failed.

 

[puncho]

Get another magazine, and use that one the range...

 

[SubNine]

Sounds like my XD45. Every time I load up full magazines, and this happens on all 3 magazines, the 8th round in each one would rattle. One of them eventually stopped rattling after using it at the range but the other two continued to rattle. I just sort of put up with it, though it still drove me nuts especially while I was carrying it concealed.

 

[EAJ]

This is not uncommon on stagger stacked mags. I've had that with my Glock mags, and seem like some others. It never seems to cause a problem though.

+1

I also have a S&W M&P 9mm SC and it does the same thing. I understand that's its quiet common with their mags. As suggested, try slamming the butt end of the mag while loading it and after it's full to seat the rounds. It helps.