What is causing this? (M & P 40) [Archive] - Glock Talk

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ZoomByU
05-09-2012, 16:04
This gun my brother originally bought as his duty weapon in middle 09. He kept having problems with it failing to go into battery so he switched to glock after the academy. He sent it back to S&W and they sent it back saying it was fixed. He has shot several types of ammo and tried brand new magazines and still the same problem. He has shot it once since getting it back and we shot it again today. This is what we got six times in 3 magazines. Any insight is welcome.

http://i187.photobucket.com/albums/x138/ZoomByU/b56e466f.jpg

http://i187.photobucket.com/albums/x138/ZoomByU/74f7d1d0.jpg

http://i187.photobucket.com/albums/x138/ZoomByU/eff73ecf.jpg

http://i187.photobucket.com/albums/x138/ZoomByU/feda1375.jpg

tbone1964
05-09-2012, 16:14
looks like the ejector is popping of the case rim when feeding could be a bad spring or a bad ejector looks like you/he is using steel cased ammo... sometimes the rims on steel case ammo are a little thicker and the ejector doesnt get a good hold on the rim. does it do this with brass?
Also clean the magazine if its dirty the spring may be binding and not pushing the round up sufficiently causing a failure to feed.. never hurts to lube the magazine body slighlty

M&P15T
05-09-2012, 16:19
Looks filthy.

Do a deep cleaning, focusing on cleaning the extractor, feedramp and chamber, get some WWB .40 ammo, and test again.

If that doesn't solve the issues, send it into S&W.

Any chance someone's fat fingers are dragging the slide slowing it down?

ZoomByU
05-09-2012, 16:28
Does this clean or dirty. This was aluminum cased ammo today. Other time was with lawman brass. Does this with original three magazines and three new ones he bought.

FLglockdude
05-09-2012, 17:27
Will a live rounds drop in and out of the barrel easily?

countrygun
05-09-2012, 17:41
Looks like, if that is a loaded round that the rim of the case is not sliding up, underneath the extractor, like it should. My guesses would range from an improperly bevelled bottom edge on the extractor, to the extractor being oversized or out of position due to shape or spring tension.

ZoomByU
05-09-2012, 17:41
Yes drops in barrel without a problem.

FLglockdude
05-09-2012, 17:57
Okay, field strip the gun, and try to place a live round under the extractor claw. It should hold the case rim just tightly enough that you can lightly shake the slide and it won't fall out. From the looks of the pictures it seems the extractor could possibly be out of spec causing the round not to chamber fully.

ZoomByU
05-09-2012, 18:34
Ok the round will go in there but I have to kind of force it in. Once it's in there I can shake the slide violently and it wont fall out. My glock it goes in smooth and will come out if shaken violently.

K.Kiser
05-09-2012, 18:40
Ok the round will go in there but I have to kind of force it in. Once it's in there I can shake the slide violently and it wont fall out. My glock it goes in smooth and will come out if shaken violently.

I'll bet your getting somehwere now..

FLglockdude
05-09-2012, 20:04
Ok the round will go in there but I have to kind of force it in. Once it's in there I can shake the slide violently and it wont fall out. My glock it goes in smooth and will come out if shaken violently.

Sounds like you may be getting somewhere.

I would give Smith a call, share your thoughts and send the gun back. All three of the M&Ps I have had including a full size .40 have been flawless.

countrygun
05-09-2012, 20:09
I'm wondering if it isn't a 9mm extractor? that is if the use different ones. It would seem that a 9mm extractor would have to "reach in further"

glock2740
05-09-2012, 20:10
Hate to hear that. My M&P40 fullsize has been so 100% that it's my night stand gun. Great gun.

ZoomByU
05-09-2012, 20:23
I think I'll call on my brothers behalf, he is kinda clueless when it comes to guns. Interesting thing is that the first time he sent it back they replaced the extractor.

ZoomByU
05-09-2012, 21:12
Here is a pic of the feed ramp and barrel.

http://i187.photobucket.com/albums/x138/ZoomByU/6edae4d9.jpg

voyager4520
05-10-2012, 05:42
In every picture the rim of the casing is failing to go under the extractor claw. That suggests either a weak recoil spring, lack of lubrication, or a "tight" extractor. The extractor may be covered in residue and gunk which won't allow it to move freely enough, or for whatever other reason the extractor doesn't move freely enough or isn't fit properly.

I'd call Smith back and tell them the "fixed" gun wasn't fixed and that you'd like a prepaid shipping label to send it back again.

fastbolt
05-10-2012, 09:56
How experienced with shooting plastic .40's is your brother?

Although any plastic pistol might be more susceptible to shooter-induced grip stability issues, sometimes you get a particular gun that might have an issue.

The same extractor is used in all M&P's, regardless of caliber. One of the neat engineering tricks in the M&P line. They're now pretty much considered drop-in parts (although armorers were required to buy .40/.357 extractor bar gauges back after the guns were introduced, in case they had to fit an extractor).

Call S&W and ask for the gun to be checked again. In the letter included with the returned gun, list the specific ammunition brands being used. They'll probably test-fire the gun with better ammo than you're using, though.

The M&P 40's have been earning a solid reputation as ammunition tolerant, reliable functioning guns among LE users (presuming normal lubrication, of course).

countrygun
05-10-2012, 10:20
How experienced with shooting plastic .40's is your brother?

Although any plastic pistol might be more susceptible to shooter-induced grip stability issues, sometimes you get a particular gun that might have an issue.

The same extractor is used in all M&P's, regardless of caliber. One of the neat engineering tricks in the M&P line. They're now pretty much considered drop-in parts (although armorers were required to buy .40/.357 extractor bar gauges back after the guns were introduced, in case they had to fit an extractor).

Call S&W and ask for the gun to be checked again. In the letter included with the returned gun, list the specific ammunition brands being used. They'll probably test-fire the gun with better ammo than you're using, though.

The M&P 40's have been earning a solid reputation as ammunition tolerant, reliable functioning guns among LE users (presuming normal lubrication, of course).

thanks for the info on the extractors. I didn't know if they used the same through out the calibers.

Wash-ar15
05-10-2012, 10:30
see if you can move the extractor with your finger. it might be tight or all gunked up. put a few drops of oil where it pivots and see what happens.

fastbolt
05-10-2012, 10:44
thanks for the info on the extractors. I didn't know if they used the same throught the calibers.

FWIW, they actually had a minor revision in the last year or so. The hooks got a bit sharper and were given a little more negative rake.

The M&P extractors are a rather robust MIM part, with a tall hook for a lot of engagement area.

Also, FWIW, last time I checked, they still didn't even offer an armorer tool in the way of an extractor bar gauge for the 9 & .45 guns (like they do with the 3rd gen guns and SW1911's). They said the tolerances of the M&P slides & extractors are such that armorers don't need bar gauges for fitting factory extractors.

countrygun
05-10-2012, 10:50
FWIW, they actually had a minor revision in the last year or so. The hooks got a bit sharper and were given a little more negative rake.

The M&P extractors are a rather robust MIM part, with a tall hook for a lot of engagement area.

Also, FWIW, last time I checked, they still didn't even offer an armorer tool in the way of an extractor bar gauge for the 9 & .45 guns (like they do with the 3rd gen guns and SW1911's). They said the tolerances of the M&P slides & extractors are such that armorers don't need bar gauges for fitting factory extractors.


Hmm......I don't know that I agree with S&W decision on that score. I am still, barring any more input, of a mind to think this is an extractor problem, BUT apparently a "rare" one.

fastbolt
05-10-2012, 11:24
Hmm......I don't know that I agree with S&W decision on that score. In what way? They've been doing a LOT of research and continued R&D on these guns since they were introduced in Jan '06.


I am still, barring any more input, of a mind to think this is an extractor problem, BUT apparently a "rare" one.

A tightly blocked (fitted) extractor can certainly create some feeding issues.

So, too, can an extractor that has become very dirty. (It doesn't require saturation with solvent/CLP in order to clean a hook, but just a good brushing. (Ever see one of those narrow end plastic brushes, using either copper, brass or nylon bristles?)

So, too, can an occasional ammunition issue.

Then, there's always the potential for the "wrong" combination of shooter grip stability, insufficient lube, low powered ammo and a dirty extractor to come together and create perplexing issues. An unfortunate nexus.

Many years ago, while discussing some feeding issues with one of the repair folks at the factory, I was told that high speed imaging could reveal that a tight extractor, or a round with a case rim that was just a bit too large/thick, could create a condition where the case would be unable to easily run up underneath the extractor hook. If that was the situation, the forces involved during cycling might cause the case to 'rebound' down away from the hook, making it almost seem as if it hadn't reached the hook (when in fact, it had).

This situation needs to be checked by the repair techs at the company. Maybe it needs another extractor, and/or maybe it needs a barrel adjustment (or simply another barrel).

How old is the M&P 40, anyway?

There have been some different revisions of followers for the .40 pistols (Glock doesn't have a "lock" on doing revisions for followers :whistling: ).

Here are the 3 revisions of the .40 followers (oldest to newest from left-to-right in both pictures). The newer ones position the rounds a bit higher (and the last round more centered), for optimal feeding in the fast-cycling .40 guns.
http://i3.photobucket.com/albums/y73/fastbolt/MP40followers1.jpg
http://i3.photobucket.com/albums/y73/fastbolt/MP40followers2.jpg

This picture shows the oldest (bottom) and the current one (top), and shows how the rounds have better support, and the follower is better positioned (against tipping) in the mag tube with the current follower.
http://i3.photobucket.com/albums/y73/fastbolt/MP40followers3.jpg

If your brother's mags don't have the current followers (displaying 40 on top), call and ask for some to be sent to you.

fastbolt
05-10-2012, 11:29
BTW, we were told that one of the reasons for the larger, more robust area on the leading shoulder of the large extractor hook was to help reduce the potential for damage to the hook if a stuck case required repeated attempts (slide manipulations) to clear the chamber.

While they still do not recommend that the barrel chamber is ever loaded by dropping a round into it (versus feeding from the magazine, as is intended), they recognized that a stoppage clearance technique (stuck case) might require letting the slide (and therefore the extractor) run forward to get another purchase on the case rim, so they wanted to make the extractor hook strong enough to resist damage to the hook if that were required for clearance.

countrygun
05-10-2012, 11:31
In what way? They've been doing a LOT of research and continued R&D on these guns since they were introduced in Jan '06.




A tightly blocked (fitted) extractor can certainly create some feeding .


I am just thinking, that if there are several different forms of extractor maybe the factory should have a tool available to make diagnosis quicker

Roger G23
05-10-2012, 11:50
Looks like steel cased ammo. We all know it's crap compared to brass. Just my .02

fastbolt
05-10-2012, 11:55
I am just thinking, that if there are several different forms of extractor maybe the factory should have a tool available to make diagnosis quicker

There's only been one revision to the M&P pistol extractor (according to the info I've received).

I was told they have production bar gauges for the different caliber models, and I'd suppose the repair techs probably have at least the same tooling available as the production folks. ;)

Also, the pistol repair folks work closely with the engineers, and therefore have what's probably described as a more current understanding of any issues that have been recognized and identified. I know that when I've asked some specific questions (as an armorer) about a couple of pistol model lines (not just M&P's), I've either been told they were getting more specific info from their engineering dept, or I got a call back from one of their engineers with answers to my questions.

They have the ability to resolve problems, even if it requires replacing the barrels and/or slides (nice thing about not having serial numbered barrels & slides ;) ).

countrygun
05-10-2012, 11:55
Looks like steel cased ammo. We all know it's crap compared to brass. Just my .02


Looks like aluminium cased Blazer

ZoomByU
05-14-2012, 07:25
Borrowed a barrel from a reliable m&p and going to take it out Wednesday or Thursday and test it out.

Dirk Pitt
05-14-2012, 13:25
I know this is probably blasphemy here but when I bought my G17 many years ago it was a total Jam o Matic. It did much what you are describing here. I played with all kinds of options, magazines, ammo etc etc. Nada same result. I did a close examination of the bolt face and it looked suprisingly rough.

I got out the evil "D" tool (Dremel) and proceeded to POLISH not SAND the bolt face, feed ramp and chamber. I used jewlers rouge and the soft wheel and worked on that bolt face until it was smooth to the touch. The feed ramp looks shiny from the factory but a few minutes polishing it and the chamber worked like magic. After cleaning, lubing and reassembly the gun now is my garbage eater. It has never failed once since that little bit of work. Regardless of ammo brand, steel, brass, aluminum, bullet weight. It just goes bang when you pull the trigger.

CAUTION: You can get into a lot of trouble with Dremel tools and guns. Lots of guns have been ruined with them. So remember if you use it -- less is more. I just did a simple polish job, and it worked.