M&P Mags Exploding (Speed Shooter Specialties)

I'm having a real problem with the SSS (Speed Shooter Specialties) base plates coming off the mags on my M&P 40L. Two mags exploded during yesterday's match, spreading mag parts all over.

Originally, I thought the problem was exclusive to the mags being dropped on concrete. I'll agree that dropping mags on concrete is tough. I'm OK with them getting scarred in the process. I'm not OK with them coming apart because they got jolted by bouncing on something hard. I had 2 mags self-destruct during a match yesterday; one landed on plywood, the other on the USPSA shooting box.

Any suggestions?

Have you got the lock plate oriented correctly? The side with the oval goes toward the spring and the side with either the dot in the center or the tab at the end is what locks the base into place. (SSS did this so both the old and new design lock plates would work, I changed all of mine to the new "tab" style because they sound like a more positive lock). I've been using those baseplates for about a year, I shoot a minimum of 2 matches a week, one of which is indoor on a concrete floor, and I haven't had any problem with the mags disassembling themselves.

Edit, just noticed your location, did you shoot the "Movember" match at RFC yesterday?

Yep, it was during yesterday's Movember match that two mags disassembled - as well as several times during practice recently. Outstanding match! Only slightly marred by the fact that this dummy blew right past a couple of sneaky targets well hidden behind barrels that I forgot about. Cost me a solid 10% of my total match time.

I'm not sure what you're talking about RE the side of the locking plates. I think S&W changed the design and mine is probably an older version.

Last week I put a dab of silicone sealant between the base pad and the locking plate hoping that the silicone solve the problem by holding the two parts together better. Instead, what happened was that the base pad and locking plate did stay together but the base pad still came off the magazine tube; it simply took the locking plate and spring with it. This happened twice yesterday with different mags.

So, today I spent some quality time looking closely at one of the base pads and mags. It seems to me that the core of the problem is that the base pad is machined improperly. There is a 0.030" gap between the base pad and the body of the magazine tube. Also, the machining of the groove that engages the tabs at the bottom of the magazine tube seems inadequately defined, especially at the rear of the base pad.

Here's a few photos of my SSS base pad, S&W locking plate and mag.

Bkreutz said:

Have you got the lock plate oriented correctly? The side with the oval goes toward the spring and the side with either the dot in the center or the tab at the end is what locks the base into place. (SSS did this so both the old and new design lock plates would work, I changed all of mine to the new "tab" style because they sound like a more positive lock). I've been using those baseplates for about a year, I shoot a minimum of 2 matches a week, one of which is indoor on a concrete floor, and I haven't had any problem with the mags disassembling themselves.

Edit, just noticed your location, did you shoot the "Movember" match at RFC yesterday?

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Let me guess, the ones you missed were on the second "wobbly bridge". I can't believe the weather co-operated the way it did. I almost turned around on the way there because the rain was horizontal and the freeway traffic was going 40mph dodging the standing water. Glad I didn't.

Looks like SSS changed the +0 mags significantly. Smith changed the locking system early last year, the first pic below shows the old and new. SSS mentioned that the baseplates will fit either system and has an additional notch machined in. The only thing the center hole is used for on the new lock plates is to disassemble them. I switched all mine over to the new locking system and they are actually difficult to take apart much less coming apart by themselves. I'd recommend calling (or contacting) SSS and tell them what's going on, maybe they'll swap them out for the updated ones (worth a shot). The newer lock plates are plastic and not attached to the spring. They're much thicker than the sheet metal ones and the situation you're experiencing is probably why they changed the design. (just a guess).

If you're talking about the double target that was behind you as you got onto the second wobbly bridge. then that's it. Stupid easy to shoot, but stupid here blew right by it. Double ugh

The other target I forgot to shoot was on Stage 4. The hard right target from the port before you went out to shoot the steel and moving array. Got 3 rounds into each down zero on the movers, but -10/FTN on the target I forgot to shoot.

On the weather - it's a 2.5 hour drive from Sequim, so I had to leave at o'dark-thirty. It rained solidly the entire way. My Ram weighs over 9000# so it the water has to get waist deep before it will aquaplane. I was ready for the rain. Had my waterproof hunting boots, tactical snow board pants (yes, tactical snow board pants - really funky but dry and warm without bulk or weight), and layers under the Carhartt rain coat, topped off with a fleece-lined waterproof bucket hat. I had my electric gloves and jacket in my cart just in case it got cold, too. I even had mud on my hat when I was done.



I recall that my mags came with the new style locking plate, but SSS base pads didn't work with them at the time and I had to get a bunch of the original style locking plates to work with the SSS base pads.

I've been exchanging emails with SSS for a week. I sent them the photos and a request this afternoon to replace the base pads . Hopefully, they'll be receptive to that.

It's a long drive to anywhere from Sequim (except P.A.) (sorry, couldn't resist). I had trouble with the colored steel stage, I'm red/green color blind, not a fun stage for me. Good thing it was a charity event and not a "for real" match.

Ouch! That would make it really hard. Bummer. You might mention it to Dave, Alan or Euan. Maybe they could use yellow instead of green.

Yeah, it's a long ways to anywhere from Sequim. But, that's also one of the beauties of the place - not too many folks like to live that far away from the clutter of urban living. It's only a couple of hundred yards from where we live to the Strait of Juan de Fuca and only about 10 minutes to the end of pavement heading inland.

OlympicFox said:

Ouch! That would make it really hard. Bummer. You might mention it to Dave, Alan or Euan. Maybe they could use yellow instead of green.

Yeah, it's a long ways to anywhere from Sequim. But, that's also one of the beauties of the place - not too many folks like to live that far away from the clutter of urban living. It's only a couple of hundred yards from where we live to the Strait of Juan de Fuca and only about 10 minutes to the end of pavement heading inland.

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Red and green targets are already illegal in USPSA (don't know about IDPA) for the very reason that red/green color blindness is the most common kind of color blindness. Like I said, it wasn't a big deal for me because it was an "outlaw" match , if it had been a sanctioned event I would have said something. It was interesting because the plates looked the same color as the background (for me), but I could see the outline of the plates, so I was shooting at a sort of "ghost ring" target , it was still fun though.

Over the years I've thought about moving to the peninsula, but life got in the way and now I'm retired and comfortable in my house so I never got around to moving. Too much work to move now. (oh, I almost missed the same target on the bridge, when I picked up the targets on the right at the end, I caught the hidden target when I glanced back, turned and shot it. That was the only stage that I shot -0. (for the benefit of anyone reading this, the match was scored using IDPA targets and scoring but USPSA rules, interesting combination)

I don't know about colored targets in USPSA as I'm new to that game, but I know that while IDPA has an extensive section in the rule book on targets, there is no mention colored targets.

I'm certain that the problem of colored plates blending with the background isn't exclusive to those affected with color blindness.
It's very easy to have a lack of contrast render targets very difficult to see in shade or partial shade conditions. It's seriously exacerbated when the targets are similar in tone to the background. I wear always wear yellow clip-ons to increase the contrast of the targets when I'm shooting.

Which gives me an idea. I'd think that a pair of either red or green clip-ons would solve the problem of not being able to distinguish red & green. They would filter out the other color in a way that results in a significant difference in contrast. For example, when taking a B&W photo of a red rose on a background of green leaves, the rose is lost because the shades of gray are nearly identical. But, with either a red or green filter, the amount of red/green light passing through the filter changes dramatically and the rose appears a very different shade of gray. Of course, both red and green filters are very dark so it would be like wearing dark sunglasses. OK out in the sun, not so OK in the shade at Renton.

Bkreutz said:

Red and green targets are already illegal in USPSA (don't know about IDPA) for the very reason that red/green color blindness is the most common kind of color blindness. Like I said, it wasn't a big deal for me because it was an "outlaw" match , if it had been a sanctioned event I would have said something. It was interesting because the plates looked the same color as the background (for me), but I could see the outline of the plates, so I was shooting at a sort of "ghost ring" target , it was still fun though.

Over the years I've thought about moving to the peninsula, but life got in the way and now I'm retired and comfortable in my house so I never got around to moving. Too much work to move now. (oh, I almost missed the same target on the bridge, when I picked up the targets on the right at the end, I caught the hidden target when I glanced back, turned and shot it. That was the only stage that I shot -0. (for the benefit of anyone reading this, the match was scored using IDPA targets and scoring but USPSA rules, interesting combination)

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What did SSS say when you called them about this issue?

Good thing your mag didn't explode while you were carrying the gun concealed...

This is why we should avoid "gamer" accessories and leave things like magazines the way they came from the factory...never heard of a factory floorplate doing this...

Here's the email I got from SSS.

Looking closely at your excellent photos it is apparent the base pads and magazines have taken some serious punishment from the dropping on hard surfaces. The rounded edges of the magazine tab and the peened base pad groove tell the story. I don't think any plastic or aluminum base pad will resist a steady diet of hard concrete landings. Nonetheless, this time I will send you 3 replacement base pads so you can get rid of the offenders.

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Hmm. What concerns me is how quickly the base pads have been affected by the wear and tear of being dropped. See, the magwell and base pads were used on the gun for only a couple of months and less than 200 rounds and all of that was at a grass range. Then the gun was converted back to an SSP gun. It stayed that way until this month. I took it with me to the IDPA BUG match at S&W and had Scott (Apex VP) redo the FSS trigger (2.1# ) and prep it for ESP again. In other words, the base pads have only been dropped on concrete a minimal number of times. Nothing at all like the steady diet that Nelson of SSS referred to.

OlympicFox said:

Here's the email I got from SSS.



Hmm. What concerns me is how quickly the base pads have been affected by the wear and tear of being dropped. See, the magwell and base pads were used on the gun for only a couple of months and less than 200 rounds and all of that was at a grass range. Then the gun was converted back to an SSP gun. It stayed that way until this month. I took it with me to the IDPA BUG match at S&W and had Scott (Apex VP) redo the FSS trigger (2.1# ) and prep it for ESP again. In other words, the base pads have only been dropped on concrete a minimal number of times. Nothing at all like the steady diet that Nelson of SSS referred to.

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If they send you the new ones with the notch for the plastic lock bases, use the plastic lock plates. I can't imagine the bases coming off with them. Like I said, I've dropped mine hundreds of times on all kinds of surfaces, never had one come apart. If you don't have enough of the plastic lock plates let me know, I'm sure I have a few lying around. When I put TF +5 and +11 extensions on, they don't use a lower lock plate under the spring so I have spares... somewhere)

I suspect you're using the SSS base plates due to the mag well extension, is that correct?

How much weight do they add?

For the record, I've dropped my mags on wood, dirt, gravel and concrete many many times and never had an issue. Now, I have a bunch of mags so, any individual mag may not have hit the ground more than yours. Still, mine have been great with the factory base plates.

dullh said:

Good thing your mag didn't explode while you were carrying the gun concealed...

This is why we should avoid "gamer" accessories and leave things like magazines the way they came from the factory...never heard of a factory floorplate doing this...

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Yeah, having a magazine disassemble itself while sitting in the holster would be a problem. Of course, that really beg the question "How did that happen?"

As for factory magazines disassembling themselves? Yes, it does happen, and from what I've heard M&P's are not immune to this problem. I'm quite certain that S&W didn't change the design of the M&P floor plate just because the engineers were bored - they were no doubt addressing some kind of a problem.

I've found threads talking about mags coming apart when dropped on the ground and even during a reload. I seem to recall a stock factory mag disassembling itself once, but can't recall which gun it was. I've also experienced other failures with OEM magazine such as rounds tumbling and magazine-related FTF issues.

However, I'll point out that this thread is about a malfunction on a competition (gamer) pistol; obvious by this point in the thread. The competition modifications done to my M&P 40L have little if anything to do with a defensive pistol. I thought that was obvious from the photo of the M&P 40L. If not, here's a photo of it in its less than concealable holster. If you look closely at the previous photos you can see the tall F/O front sight and adjustable rear sight, the modified grip and extremely coarse grip tape. And then there is that fast Apex competition FSS trigger with a light 2.1# pull.



I also have M&Ps for CCW.

The M&P Shield & its holster . . .





And the M&P 9c and its holster





As for keeping a gun the way it came from the factory?

If you believe that a perfectly stock gun is better and more reliable than one with sensible quality upgrades, then by all means, keep your guns stock.

I don't subscribe to that belief, and very, very few of my guns are the way they left the factory. None of my handguns, not even my Ed Brown and Nighthawks are factory stock. Each has had something done to it to make it function a little better for what I want that gun to do.

If you go back and look closely at my CCW M&Ps you'll see that I've made a few improvements. Both have Tru-Glo TFO fiber optic night sights so that I can shoot them faster and more accurately than with the factory 3-dot sights. Both have Talon grip tape so that the gun doesn't slip in my hands, regardless of the conditions. Both have Apex Duty triggers that are easier to shoot well than the OEM triggers, yet still require ample pull effort (over 6#) to be a safe defensive pistol.

Rastoff said:

I suspect you're using the SSS base plates due to the mag well extension, is that correct?

How much weight do they add?

For the record, I've dropped my mags on wood, dirt, gravel and concrete many many times and never had an issue. Now, I have a bunch of mags so, any individual mag may not have hit the ground more than yours. Still, mine have been great with the factory base plates.

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Yes, I'm using the SSS base pads because of the mag well.

How much weight do they add? Well, let's see. Just for kix and because I'm the Prince of Anal, I used my RCBS powder scale.

OEM Plastic Base Pad: 91.0 grains (0.21 oz)
OEM Plastic Locking Plate (rear tab): 21.9 grains (0.05 oz)
Total: 112.9 grains (0.26 oz)

SSS Base pad: 476.6 grains (1.09 oz)
OEM Metal Locking Plate (center hole): 57.4 grains (0.13 oz)
Total: 534.0 grains (1.22 oz)

So, there you have it - the difference is just 0.96 ounces using the heavier metal locking plates. Just barely IDPA legal.

Bkreutz said:

If they send you the new ones with the notch for the plastic lock bases, use the plastic lock plates. I can't imagine the bases coming off with them. Like I said, I've dropped mine hundreds of times on all kinds of surfaces, never had one come apart. If you don't have enough of the plastic lock plates let me know, I'm sure I have a few lying around. When I put TF +5 and +11 extensions on, they don't use a lower lock plate under the spring so I have spares... somewhere)

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Thanks for your offer!! Fortunately, there is an advantage to being totally anal. I have individual spare parts storage boxes for each type of gun in our collection. Each individual gun has its own ZipLoc bags in the storage box. Big boxes for guns we like a lot and have lots of - like M&P's and 1911's. Itty bitty boxes for guns we don't like so much - like our token Glock 34.

In other words, it only took a second to find the 8 OEM plastic locking plates with rear tabs and OEM base pads.

My "plan" is to shoot USPSA in Limited with the M&P 40L and my NHC's in Single Stack. The 1911's didn't need any additional mods, but the M&P needed additional capacity. So I ordered some new TF base pads yesterday; 4 of the TF 129.5mm (+3) that I can also use in IDPA and 4 of the 140mm (+6) for USPSA.

I only recently started shooting USPSA at Kitsap; first with my 9mm NHC in Single Stack and last month with my uber competitive M&P 9c in Limited 10. Yeah, an M&P 9 Compact in Limited. It has the Apex FSS trigger in it so I can't run it in Production. I used it in the IDPA BUG Nationals a couple of weeks ago so I ran it in a few IDPA and USPSA matches, even a Classifier, for practice. It was great fun trying to keep up with the bad boys & their souped up STI's. My biggest problem was keeping body parts out of the way of the mag during reloads. Came home with several blood blisters on the heel of my hand and pinky finger.

You might want to check the rule book on the 129.5 extension. I believe that extension was made to conform to IPSC rules, not IDPA, I don't think IDPA allows any base that adds capacity. Even if they did, 10 is the maximum allowed in either SSP or ESP (except 11 for the first mag before making ready, and classifiers). I could be wrong, but that's the way I remember it. Another hint, when you get the TF extensions, make sure you don't put either the metal or plastic lock plate on the bottom of the spring, it makes it more difficult to disassemble, and you lose 1 round of capacity. (I didn't read the directions and found out the hard way )

Bkreutz said:

You might want to check the rule book on the 129.5 extension. I believe that extension was made to conform to IPSC rules, not IDPA, I don't think IDPA allows any base that adds capacity. Even if they did, 10 is the maximum allowed in either SSP or ESP (except 11 for the first mag before making ready, and classifiers). I could be wrong, but that's the way I remember it. Another hint, when you get the TF extensions, make sure you don't put either the metal or plastic lock plate on the bottom of the spring, it makes it more difficult to disassemble, and you lose 1 round of capacity. (I didn't read the directions and found out the hard way )

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I talked to Taylor about the 129.5 mag extension and he said it fits in the IDPA box & is IDPA legal. The IDPA rules do allow for aftermarket & modified base pads with two provisions:
a. The gun must fit in the box with the magazine used in the match.
b. The magazine may not weigh more than 1.00 ounce than the same capacity factory magazine. Since IDPA doesn't allow more than 10 rounds loaded in the magazine (except for Classifier Barney mag) the extra capacity is a mute issue.

I'll have to double-check the weight difference. I'm accustomed to having some of my guns right on the edge of the rule. For example, IDPA changed the rules on revolver grips outlawing the Hogue "Bigbutt" grips, etc. So, I put my grips to the sander until they fit the new rule. One of the SO's at this year's S&W Indoor Nationals actually tried to buy them off me.

Before:



After:

I don't like trying to get right to the limit of rules, that's why I shoot USPSA Open.(almost no rules) I got rid of my last revolver about a year ago (M29, my wrists couldn't take the beating anymore). But that's why there are different sanctioning bodies and divisions, place for all of us to play. I'm waiting to see what the IDPA rulebook looks like after they eliminate the "flat footed reload" rule, I got nailed for 7 procedurals at the State Championship, kinda soured me on the whole thing. The match last weekend was the closest I've gotten to an IDPA match since then. That silly rule may have been the last straw for me. I overheard some of the staff bragging to each other about how many procedurals they gave out, that attitude, in my opinion, has no place in the sport.