M&P Fixes and Upgrades

[ricklee4570]

I just bought a new M&P 9mm. The fired cartridge case that came with the gun is dated 12-2009.

I know that there were some problems with the early guns and that throughout the years improvements were made.

In particular I know that a new firing pin ( striker ) was developed, and I heard that there was some sear "flutter" problems that were corrected. How would I know if my gun has all the improved parts in it? The build date is probably around August to November 2009 since it was test fired December 2009. I also heard that different sights were incorporated at one time as well?

 

[eclypse]

Wow, 2009? My recently purchased M&P9c was test fired at the end of February of this year.

 

[ricklee4570]

I was a little surprised too. They had two 45's and two 9mm's and all four had the little envelope that contains the fired cartridge case. All were dates December 2009.

I have heard that there were some issues with the early M&P's experiencing "dead triggers" where the sear wouldn't reset reliably. Usually showed up after a thousand rounds or more were fired in it.

 

[SkiNut]

M&P 40c

I have a 40c from that time and it had the older Striker which is black in color. My understanding is that it is a little brittle and could shatter. I installed a new one I bought at Brownells for $25 and it's Stainless Steel so it's bright in color. Thats the only problem I know about. Good Luck!

 

[SMMAssociates]

ricklee:

The striker is probably the main issue.

SOME M&P's are now in the pipeline with a sear block that includes a larger sear return spring and plunger. A definite plus - S&W won't swap 'em, though, unless you have a problem, but Apex will drill out the plunger hole and provide a new plunger and spring. If you've purchased their DCAEK (or other sear replacement) kits (to which you should add their RAM kit if you don't have a thumb safety and don't want your Hilary Lock if you've got one) it's a tad cheaper....

This is NOT a DIY.... Getting the plunger hole drilled correctly requires a decent machinist and a good mill. I think Apex would sell you a plunger, though. The proper spring comes with the DCAEK kit. (The "upgraded" sear block, without any other parts, is usually called "Massachusetts Compliant", and has actually been around for a while, but is becoming standard. Unless you actually bought a MA-Compliant gun, you almost certainly didn't get one.

I can't think of anything else, but I'm sure somebody will ....

Nothing in the gun that can't be swapped if you can find a source....

Regards,

 

[sabrecross03]

I also purchased a M & P 9c last month and the test date was Jan '09. I bought it slightly used and I've put about 1200 rounds through it. No problems so far and I'm keeping my fingers crossed.

 

[ricklee4570]

ricklee:

The striker is probably the main issue.

SOME M&P's are now in the pipeline with a sear block that includes a larger sear return spring and plunger. A definite plus - S&W won't swap 'em, though, unless you have a problem, but Apex will drill out the plunger hole and provide a new plunger and spring. If you've purchased their DCAEK (or other sear replacement) kits (to which you should add their RAM kit if you don't have a thumb safety and don't want your Hilary Lock if you've got one) it's a tad cheaper....

This is NOT a DIY.... Getting the plunger hole drilled correctly requires a decent machinist and a good mill. I think Apex would sell you a plunger, though. The proper spring comes with the DCAEK kit. (The "upgraded" sear block, without any other parts, is usually called "Massachusetts Compliant", and has actually been around for a while, but is becoming standard. Unless you actually bought a MA-Compliant gun, you almost certainly didn't get one.

I can't think of anything else, but I'm sure somebody will ....

Nothing in the gun that can't be swapped if you can find a source....

Regards,

Thanks for the information. I really like this gun. This particular M&P has a great trigger (the others in the store were heavy and gritty). This one is crisp and just right. I got lucky there.

The striker is silver in color.

I am concerned about the sear though. If the gun shoots reliably for a thousand rounds and then in a self defense situation it malfunctions, that could be catastrophic.

My local gun dealer says that if it was a problem S&W would have recalled them as many police officers carry them.

Is this problem limited to a certain caliber or model of M&P?

 

[SMMAssociates]

ricklee:

The silver striker is the one to have.... +1 there ....

The replacement sear improves the trigger, but isn't otherwise necessary. However, with the replacement sear, and in some cases, without it, you can run into the dreaded "dead trigger" problem....

Essentially (seems to be some combination of dirt and sloppy tolerances), the sear doesn't move into the right place to grab the striker during recoil, and the gun won't fire. There's no "cocked" indicator, so you really don't know unless you are quite into the feel of the trigger, and I wouldn't trust that.

If you have the problem, S&W will fix it.... But it's probably wise to schedule a replacement long before that, and S&W isn't being a lot of help there. It's quite easy to swap the whole mess (you can get replacement sear blocks from Brownells and Midway), but nobody's saying much about which version they're stocking/shipping at this point. You need a good mill and a machinist to do this, unfortunately....

The good news is that it's inexpensive, and you can remove the sear block and mail that any old way (Apex likes FedEx or UPS for tracking) 'cause the sear block is not considered a firearm, and doesn't need any of the expensive shipping magic. Turn around was pretty quick, too....

(I have three M&P's. One needed the fix as soon as I put the DCAEK kit in it. The other two are fine. They're on the list - one of these days....)

This seems to be the same for all of the smaller caliber M&P's - 9mm, .357 Sig, and .40. They use the same innards, although the 9mm slide's breech face is a tad smaller. You can buy a 9mm barrel and magazines from somebody and put 'em into the .40 like the gun came that way.... Aftermarket 9mm barrel, though - they appear to be made to fit the .40 slide. You can't put a .40 barrel on a 9mm slide, though.

The .45 versions are slightly different, and less interchangeable, but the dead trigger seems to turn up there, too. The fix, in all cases, is a somewhat larger spring and plunger to return the sear to it's proper place to grab the striker during recoil.

Search on "Dead Trigger" and you should find more.... Seems like some guys will report "never", and some will report (as I did) "it happened before the 'new' wore off."

S&W is slipstreaming the new sear blocks into production, but unless you get a MA-compliant gun, it's still a coin toss....

Regards,