New M&P Owner w/ Problems

[wkywthunter]

Update: I went ahead and called S&W. I told them the issue I was having with the Federal 180gr FMJ. They said that they have not had any problems with M&P40's shooting ANY ammo out there. He first said he would send me a pre-payed shipping label, but I recommended trying the latest followers first. He eventually agreed that would be ok to try, so he is sending me 3 new followers to try first.

Again, he said some sidearms tend to prefer some ammunition over others, but that wasn't really the case with the M&P. He said it should eat whatever you feed it, as lond as it was made to SAMMY specs, which I'm pretty sure Federal ammo is... or supposed to be.

As for the followers, it may be a while, because they are indeed on back-order. It could be 4-6 weeks, although he said they could very well be here much sooner.

 

[wkywthunter]

Well, that was a short 4-6 weeks. They came in the mail today! I plan to shoot again on Monday. I'll report whether the new followers solve the problem or not.

 

[wkywthunter]

Well, I know it's been a while since I posted, but the followers didn't work. I called S&W back, and they sent me a label, and I sent the gun in. When it came back, IT WILL SHOOT ANYTHING. Anything I have put it in so far, anyways.

It came with a receipt telling me what was done to the gun, what was listed was:

"Barrel Modification"
"New Extractor"

All that I could tell that they did was put a chamfer around the mouth radius of the chamber. But it worked.

I'm not sure why they put a new extractor in it to fix a feeding problem... Who knows, maybe they shot it and had an issue with the ammo they were using.

Anyways, S&W made it right, and that's what counts. I've shot probably 250 rounds through it or more since I got it back.... 0 malfunctions.

I'm pleased with the response.

 

[chuck s]

A bad extractor can prevent good feeding. The cartridge rim slips up and under the extractor as the cartridge is stripped from the magazine.

If the cartridge doesn't slide easily under the extractor a stoppage can occur. Exactly what was happening in your stoppage.

The pistol should feed with NO extractor, but an overly tight extractor or one with lots of crud under it can cause a stoppage.

-- Chuck

 

[AJW]

I'm glad to hear it all worked out. A testament to S&W customer service and commitment.

 

[Fastbolt]

Glad to hear it.

Yep, the extractor can sometimes cause some feeding issues, even if it doesn't look like it's involved, like when the case rim is still beneath the extractor and doesn't appear to have started to engage it. Under high speed movement during cycling the rising round can actually hit a tight extractor and be 'bounced' back down below the extractor (this has been observed in high speed imaging). Of course, a tight extractor can also cause problems where the case rim is caught up under it, which is probably more commonly recognized as a potential extractor issue.

The extractors in the M&P's are essentially drop in parts because of the newest tolerances and manufacturing, but they're still checked with a production gauge when they're made. I checked mine with an armorer extractor gauge, just out of casual interest, and mine was on what I'd call the looser end of the acceptable range (if it were an 3rd gen gun), so I could see how one might slip through which might have been on the tighter end. A loose one can be adjusted by filing on the adjustment pad of the extractor, but one that's too tight is usually just replaced (since you can't add metal and it obviously wouldn't help to remove any more metal ).

It's also possible that when the repair center was taking a very close look at your gun that they may have seen something about the extractor hook dimension as manufactured which slipped by during production, too.

My M&P 40c has fed any ammunition I've run through it, including something like 5 or more duty JHP loads I've been issued over the years and still have in my range ammo collection.

Ammunition variability isn't exactly unexpected, though, and some judicious relief at the chamber mouth (done by someone knowledgeable, so another problem isn't created), combined with a change in the extractor, can sometimes make an individual gun much more tolerant of ammo tolerance variability.

Enjoy.

 

[Steve M.]

I had the same issue with a .40C that I had as a BUG/off duty gun. Fired about 300 rounds through it with nary a problem. Took it to the range to qualify with it and couldn't get it to feed consistantly. Ended up being the range ammo (I checked some of the rounds with a micrometer and they were too short). New box of ammo and it went w/o a hitch. I got LOOOOTS of practice with malfunction clearance drills. I got issues a .40 fullsize and love the gun. Went a week later and bought a .45C. Damn Smith and Wesson: they are costing me too much money!