Update:

Tried it with the Apex extractor tonight. First 50rounds, flawless. Round 65, the last one in the magazine was an FTF, bullet nose jammed up against the top of the chamber, tap on the back of the slide and it went into battery and I was able to fire it. Then round 100, the last round in the magazine FTF with the round straight up and down vertical in the ejection port. I will say this, the Apex extractor flings out the empty shell cases with authority.

At this point I'm at a loss for what to do with it. Really had to fight the urge to throw it out the window as I was driving across the bridge over the Matanuska River on the way home tonight. The only other thing I can think of is to try a new magazine. I just hate the idea of throwing more money and effort into polishing this turd.

Original Post:

So I've had a 4" M&P 10mm for a while now and it's been notoriously unreliable despite 2 trips to Smith & Wesson and parts replacement and polishing by me.

Originally it constantly failed to feed the second to last round in the magazine. Did not matter how many rounds were loaded in the mag or type of ammo, every single time it failed to feed the second to last round in the magazine and the point of impact was consistently way low to the point of being off the paper at more than 10 yards.

First trip back to Smith and Wesson and the barrel was replaced. Still consistently failed to feed the second to last round in the magazine but at least it's shooting to point of aim. Switched to Wolff extra power magazine springs for the .45 M&P, no difference. Sent back to Smith, returned with a note stating that pistol was function checked with no issues. No difference. Switched to Galloway Precision 24lb. recoil spring assembly. No difference. Polished the feed ramp and the chamber. It worked flawlessly for 1 range session where 3 of us put over 400 rounds through it.

Two weeks later, back to failing to feed the second to last round in the magazine. Switched to Springer Precision magazine springs. Now getting random failures to feed, still jamming the nose of the bullet against the roof of the chamber, but now no longer consistently with the second to last round in the chamber.

Was cleaning it this afternoon and started comparing to my Sig X Ten. The Smith is so much lighter and easier to carry that I really hate to give up on it. Ordered the tool steel extractor from Apex. I don't think I've ever had this many issues with reliability in a pistol. I really want to like it, it's unique in being Glock 19 sized but in 10mm. I'm looking at the Apex extractor as being the last chance for this pistol before I finally throw it in Prince William Sound...

This message has been edited. Last edited by: 2000Z-71,

So, not kidding. Your options, in my opinion, are G20 or G40. Flawless 10mm goodness.

Ugh. I REALLY hate to hear that. Brand new one at home right now. I do hope you get it working, but I also hope it was a one off, and not a pattern.

quote:

Originally posted by Anubismp:
So, not kidding. Your options, in my opinion, are G20 or G40. Flawless 10mm goodness.

My Sig X Ten has been flawless, it's just bigger and heavier than the M&P. Not a problem for open carry in a chest holster, it's just little much to carry concealed.

Sorry to hear this. How about a G29 if it doesn’t work?

Magazine feed lip geometry?

quote:

Originally posted by 4MUL8R:
Magazine feed lip geometry?

Possibly. I've got an M&P in 40 that has never given me a problem. Comparing the magazine to the 10mm, the feed lips for the 40 are almost twice as long. So longer cartridge, shorter feed lips, I don't get it.

If only Sig would make a 10mm compact Exchange kit you'd be all set. They have all the parts available already except a compact barrel, compact magazine and maybe a resprung compact recoil spring assembly. If you could settle on a Carry version, you could just use the full size magazines. I wish Bruce Gray would make one as a proof of concept.

You tried several mags?

I doubt S&W will do much more since you did your own gunsmithing and “polished” stuff on it yourself.

Try new mags if it still does it. Sell it and buy a real 10mm like a 1076 or a Glock 20/29/40

Shouldn't sell a piece of garbage, recycle the metal parts and smash the rest of it with a sledge hammer throw it in the landfill.

In you care to give this experiment a try a tiny amount of insight might be gained. Try firing your M&P using only one round in the magazine and one in the chamber if you have not done so already. You might also try it with a clean versus a slightly dirty feed ramp. You might spring for one more new magazine too.

I'd try different brands of ammunition and perhaps record the overall lengths of the rounds (and bullet brands/weights/design, i.e., fmj vs jhp) tried and noting if there is any correlation with their failure to feed. It is quite plausible that S&W's test ammo is far different from yours. There is an unusually wide spectrum of bullet weights available and used in 10mm, from 135 gr to 220 gr before even considering the RNL, CMJ, FMJ, JHP choices.

The feed problems I have encountered have been combustion residue on the feed ramp and chambers in 10mms with tight target grade barrels' chambers as such crap can accrue there quickly and require a wipe after several magazines have been fired or else they suffer a failure to feed. The other issue is just magazines themselves, even in the same brand, while being visually and dimensionally identical.

IMHO the secret dimensions and geometries of magazine feed lips are dark, deep, and withheld from ordinary human beings never to be revealed. Additionally some magazines seem to have been cursed so as to always fail and are irredeemably evil. So perhaps a tenacious persistence or a top drawer gunsmith might solve the issue or you could just put it back in the safe and let it gather dust.

I went through the same issue with my M&P 10. With max oal length ammunition the pistol jams with six or seven rounds in the mag. I tried to overcome this with a heavier recoil spring. The recoil spring was not the problem. I found that if I reloaded the ammo a few thousands shorter, voila problem solved. This came from Montana Bullet Works.

“From a customer–we couldn’t have said it any better: At first they wouldn’t feed in my glock 20 with KKM barrel. Additionally, the wide metplat rubs the side of the magazine when you stuff 12 or so in there at SAAMI length. After some experimentation, I found they function flawlessly at about 1.22-1.23” overall length. Of course this is slightly deeper than recommended for the 10mm, but working up from a starting load slowly gave me no issues. Brinn”

This doesn’t help non reloaders. But here’s another explanation, a picture I found on the web.

https://www.sigtalk.com/attach...magazine-gif.469522/


I hope this is of some value.

Andy

Surprised nobody has offered up the P220 10mm. Overbuilt, 100% reliable...just a tad on the heavy side, which is actually quite nice for the hot rounds.

Update at top.

Man, that sucks. At this point, I'd try a new mag just to be sure...you have so much time and money invested already that it would be a shame not to exhaust every last possibility.

I'm not really an M&P fan, but I actually got excited about these when they came out. On paper it offered some things that the Glock didn't, half the price of the Sig and lighter, and it wasn't an XD, so I thought I might actually have found an in-production 10mm that I could live with. My personal experience with a couple examples that some shooting buddies bought (how the heck could Smith let a single gun, much less a whole product line, leave the factory with a trigger like that?!?!), coupled with your experiences have made me cross them off the list of possible 10mm options for me.

OK, this has gotten down to desperation and the attitude of, "It's not stupid if it works."

I've got one of first versions of an M&P Pro Series in .40S&W. I've never had a single a single malfunction with. Started comparing magazines between the two again. It looks like for the 10mm magazines, Smith squeezed the top in of the .45 magazines rather than make the .40 magazines deeper. The geometry at the top of the mags are totally different. The feed lips on the 10mm magazines are about half the length on the .40. I don't get it, longer cartridge, shorter feed lips.

Started experimenting with them. With a single round loaded in the 10mm magazine, I can lift up under the nose of the bullet and turn the round completely vertical in the magazine. I cannot do that with a round in the .40 magazine. Also started looking at the followers, they have a different geometry as well. Obviously the 10mm is longer front to back. But the .40 has a slightly wider shelf on the left side of the follower at the top. Basically it shoves the last round on top of the follower further to the right of the magazine.

Thought what the hell, try a .40 follower in a 10mm magazine. It seems to work hand loading and unloading with the .40 follower I can no longer turn the round vertical in the magazine by lifting up underneath the nose of the bullet. Since most of my issues have been with the second to last round or last round in the magazine, who knows, this might actually work.

Call S&W, tell them the problem still isn't fixed and they should send a call tag for it.

Put the stock extractor back in and let them deal with it, you paid for the gun and the warranty, let them make it right, fix or replace it.

I find this kind of amazing. I would think S&W could have straightened this out by now. I wouldn't trust that gun no matter what they did at this point.

The follower thing makes sense. I'm intrigued to see how that works at the range. If it does solve it, I wonder if 3D printing some custom followers might the be long-term fix.