M&P Magazine basepad issues

S&W recently changed the design of the basepads for the M&P series guns.  Here’s a picture of the redesigned basepad that I have on all my M&P Pro Series magazines in .40 S&W.  Sorry for the picture quality, all these were taken with my iPhone at the range.  Click any image in this post for the fullsize version.  Back to the issue, notice on the basepad the location of the pin/hole that retains the basepad to the magazine floorplate and body.  It’s pretty far to the rear compared to earlier models which had the pin located in the center of the basepad.  I didn’t think this was a problem until I dropped an unloaded mag doing a reload and heard a “sproing” as my magazine came apart.  The spring and follower went one way, the floorplate went downrange, etc.  I recovered all of the parts except the floorplate, and started inspecting them to see what happened.  When I got to the basepad, I found the following area of concern.

The basepad is cracked immediately to the right of the hole where the pin on the floorplate goes.  This caused me a moment of consternation, so I checked my other three mags.  Obviously, one mag is fine as I used in the picture, however my other two mags also have the same crack in them.  Observe the damaged magazines.





So I have 4 magazines, three of which have cracked basepads.  Only one of them has failed, mind you – the other two with the cracks in them are still running just fine and haven’t come apart when I drop them.  I honestly don’t know what to make of this.  On the one hand, two of the magazines have continued to function flawlessly despite repeated drops while cracked, and so really my failure rate is only 25%.  I am wondering though if anyone has bought an M&P recently and noticed that the basepads are cracking, if so it would represent a wider issue than just my mags.

Also bear in mind that I’m hard on gear.  These magazines get dropped on unforgiving concrete floors pretty repeatedly, as I do most of my practice at indoor ranges these days.  Like I said, I’m curious about this issue, and I want to see if continuing to drop the magazines will eventually 1) crack the one that isn’t cracked and 2) cause the others to fail.  I’m also going to order a couple of these M&P 10 round magazines and see if they have similar issues.

I will say that other than that, I’m extremely happy with my M&P in .40.  It shoots soft, is extremely accurate, and generally speaking is the ideal of what a competition designed polymer pistol should be.


  1. It has to be a design flaw, all the cracks are identical, random breakage due to dropping should be in different places. If they all break in the same place there has to be a weak spot there for some reason.

    Can you get a metal replacement basepad?

  2. Yeah they’re all going to break like that. It’s possible your polymer base pads were all from a substandard lot or something, but realistically somebody screwed the design up.

    Among other things, the hole in the base pad shouldn’t be square. You’ll notice that the cracks all start at the corner of the square hole and then spread to slightly locations on the edge of the base pad. The corner is acting as a stress riser and crack nucleation site.

  3. This is why I laugh when everyone complains about the price of HK magazines. Sure, they are pricey, but just about the only thing that will break them is running them over with a vehicle.

    1. The sad thing is the M&P mags really aren’t that much cheaper compared to P30 mags.

    2. Iv’e seen two HK USP compact .40 mags have their welds break on the back of the mags causing them to split apart. So all mags at one time or another can have problems. I see it all the time as a LE firearms instructor.

  4. 10-8 Performance makes an aluminum floorplate that Brownells stocks. I’d add a link, but I’m sending this from the phone.

  5. Jeff the Baptist nailed it. A square hole that close to an edge is a design flaw any sophomore engineering student should be able to recognize and avoid.

    I would not rely on these magazines for anything, and especially not for carry (if any of your carry guns use them).

  6. @IZ:
    Aluminum base pads probably illegal in IDPA and need to make weight for USPSA production (max is listed weight + 2oz).

    (IDPA rule says the following is not allowed: Add-on weights for a competitive advantage (this includes,
    but is not limited to, weighted magazines, tungsten guide rods,
    brass magazine wells, weighted grips).)

    I wonder why they changed the design.

    1. The problem with the alloy basepads is that they’re drilled for a center hole – the new design of the magazine floor plate won’t work with those.

    2. Ah, I missed that there’s a definition of weighted magazine at the end of the book. Don’t get me started on the IDPA rulebook.

  7. If you search Brownell’s for “M&P” and “Magazine butt plate catch” you should be able to find the old style that works with the 10-8 base pad (assuming I’m using the correct product term). Anyway, Brownells’ should carry the old style locking plate, or whatever it’s called. A retro-fit, if you will. The problem with the stock base pads is their extended lip. 1.) it creates awkward indexing of the mag during reload, and 2.) the mag you are drawing will commonly grab the base pad lip of the magazine behind it. I Shot USPSA this weekend and saw it happen to a Master shooter. It’s happened to me as well. This doesn’t happen with the 10-8 pads, and the magazine fits the hand better during draw and reload. All hail 10-8’s awesome manna from heaven.

    1. I think was what I disliked the most about the M&P – the magazine floor plate…

      The little ones slide off, the big ones stay put but are totally too long.

      10-8 is cool beans indeed…

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