40c Firing Issue

[EXERCISINGTHE2ND]

This may be hard to explain so I may need to clarify.

As the gun fires, the slide moves backwards, ejects shell.

Then it feels like the slide stops for a moment, then snaps forward picking up the next round. I am use to a very quick back and forth of the slide without a feeling of momentum of the slide moving forward.

So, is it:
1) ammunition (Federal FMJ 180g - no issue berfore)
2) ammo hanging on slide
3) something with the sear
4) something with grip like not locking wrists
5) something with the recoil spring
6) something else

Also, 100 rounds more have shot than in my signature.

Thanx for any help or advice.

 

[xzhync]

I just bought a 40c a month ago and am experiencing the same thing. Mine is currently back at S&W being looked at. I noticed it right away. The slide has a herky-jerky feel to it. Feels like something interferes with the slide travel and somehow the momentum is messed up. It is hard to put into words, but it just doesn't feel right...sort of an unsettling feeling like it might not make it back into battery. Mine hasn't failed yet, but I thought I should send in to be looked at. I have owned a number of automatics in 9mm and 45 Acp, but this is my first .40 cal. I have never experienced this effect with any other gun. I hope it isn't a "40 thing". I amreally at a loss for what is causing this.

I have a feeling that I will get it back with a note that says everything is in spec and that there is nothing wrong. It is tough to describe the problem, so I bet it will be hard to diagnose.

 

[EXERCISINGTHE2ND]

Thanks for the post. Can you post when you get it back, please?

 

[xzhync]

Thanks for the post. Can you post when you get it back, please?

Yes, I will post once I get it back and test it. I called yesterday and the cs said it had not been looked at yet. I may not see it for another week or so.

When you posted your issue I was hoping other 40c owners would chime in to say whether or not their 40c displays this same "odd" slide movement. I had posted my issue several weeks back and didn't really get any folks responding with a similar experience.

 

[mewisemajic]

Sounds like the ammo shortly hanging on the feedramp before the power of the recoil spring forces the round into the chamber.

 

[xzhync]

Sounds like the ammo shortly hanging on the feedramp before the power of the recoil spring forces the round into the chamber.

That is possible. Does seem like something is impeding the slide travel. In my case it seems to happen more with the 10 round mag. I noticed the mag spring is pretty strong. That could be making it difficult for the slide to strip off the round.

 

[dfhawkins]

I've not experienced any interruption of the slide cycling as described. In fact, the M&P 40c was smooth and flawless when used in USPSA competition using both compact and full size magazines. The only negative with this gun was a front sight falling out. (S&W replaced the slide and sight within 10 days door to door.)

My only complaint is that I could be as smooth and flawless in USPSA matches as the 40c.

 

[robkarrob]

If it is the ammo hanging before being slammed into the chamber, then there is an easy check. Load a round in the chamber, drop the mag and fire. Do you get the same feeling of hanging? If so it is not an ammo loading issue as you eliminated the mag. If this eliminated the issue try shooting with one cartridge in the magazine. If ok add a second cartridge in the magazine, etc, until you fine how much mag. spring pressure is needed to create the problem.

Let us know how you make out.

Bob

 

[hkyplr]

Yes, I will post once I get it back and test it. I called yesterday and the cs said it had not been looked at yet. I may not see it for another week or so.

When you posted your issue I was hoping other 40c owners would chime in to say whether or not their 40c displays this same "odd" slide movement. I had posted my issue several weeks back and didn't really get any folks responding with a similar experience.

I got my 40c about 3 weeks ago, I think it was right around the time I read your other post. I have fired about 200 rounds through it or so and what you have described has happened to me once. It does feel strange and I hope it is a isolated incident.

 

[S&WOkie]

I have not had any issues when firing the .40 caliber from my M&PC.

 

[turbo38gn]

I have not had any issues when firing the .40 caliber from my M&PC.

I have to agree here... but I do seem to remember one of my M&P's... seeming like the slide was in slow motion a time or 2... maybe it was ammo or lube related, but nothing that affected the operation of the gun at all in a negative way...

 

[xzhync]

Thanks for the post. Can you post when you get it back, please?

Got my 40c back from S&W. took it to the range yesterday and it has the same problem with sluggish slide movement. No improvement whatsoever. The paperwork said they did a "barrel modification" (couldn't see any evidence of a change), replaced the extractor and extractor spring. When I saw that report I was almost sure that they had not addressed the issue. I am no expert, but I know enough to know that what they did had no relevance to the issue. That tells me they were clueless or didn't care to take the time to solve the problem.

I have the same problem...actually now it is worse. The slide now locks back prematurely on the occasional shot. I made sure my thumb was nowhere near the slide lock lever. I guess they are hoping I will just go away.

 

[mewisemajic]

Got my 40c back from S&W. took it to the range yesterday and it has the same problem with sluggish slide movement. No improvement whatsoever. The paperwork said they did a "barrel modification" (couldn't see any evidence of a change), replaced the extractor and extractor spring. When I saw that report I was almost sure that they had not addressed the issue. I am no expert, but I know enough to know that what they did had no relevance to the issue. That tells me they were clueless or didn't care to take the time to solve the problem.

I have the same problem...actually now it is worse. The slide now locks back prematurely on the occasional shot. I made sure my thumb was nowhere near the slide lock lever. I guess they are hoping I will just go away.

I hate to hear that. Not a good report. This is one reason I haven't bought a second M&P. It seems like S&W wants to get guns out fast rather than getting them out with reliability first. Glock is similar with their Gen4s.

 

[EXERCISINGTHE2ND]

Got my 40c back from S&W. took it to the range yesterday and it has the same problem with sluggish slide movement. No improvement whatsoever. The paperwork said they did a "barrel modification" (couldn't see any evidence of a change), replaced the extractor and extractor spring. When I saw that report I was almost sure that they had not addressed the issue. I am no expert, but I know enough to know that what they did had no relevance to the issue. That tells me they were clueless or didn't care to take the time to solve the problem.

I have the same problem...actually now it is worse. The slide now locks back prematurely on the occasional shot. I made sure my thumb was nowhere near the slide lock lever. I guess they are hoping I will just go away.

What are you looking to do next?

 

[xzhync]

What are you looking to do next?

I have been trying to weaken the mag spring over the past few days. I keep thinking that the slow/labored slide movement may be caused in part by a tight mag spring which is making it tough for the slide to strip off a round. I tried the test mentioned above where it was suggested to chamber a round then drop the magazine. I tried that several times and didn't notice any problems. I am going to take it out one more time probably tomorrow to see if there is any improvement. If not, I will try to see if my dealer will allow an exchange for another gun.

 

[CrossRifles2008]

Don't seem to have that trouble with my 40c. Its seems slow but doesn't fail to feed right? Have you tried bringing multiple types of ammo? I use Remington UMC 180 grain jacketed flat nose. The ones in the 250 value box. I've also shot a 50 box of Federal Value hollow points without trouble. Just seems odd. Maybe with a few hundred more rounds it will break in.

 

[xzhync]

Don't seem to have that trouble with my 40c. Its seems slow but doesn't fail to feed right? Have you tried bringing multiple types of ammo? I use Remington UMC 180 grain jacketed flat nose. The ones in the 250 value box. I've also shot a 50 box of Federal Value hollow points without trouble. Just seems odd. Maybe with a few hundred more rounds it will break in.

My 40c doesn't fail to feed. It just has very sluggish slide movement intermittently. It feels very odd when it happens.

I went to the range today. I had been trying to compress the mag spring for the past 5 days. It didn't work so while at the range I cut a coil off of the mag spring. I noticed an improvement, but I still had some slide sluggishness. I clipped off 1 more coil and then I didn't notice any more problem. I think the problem is that the mag spring was too strong for the recoil spring. I will try and go back to the range next weekend to do one more check. If I don't notice any problem I will believe that my fix truly worked.

I know some folks on this forum have said not to cut the mag spring, but after I did the problem went away. I tried some rapid fire and the mag spring was still plenty strong enough to support fast cycling.

I may not have mentioned previously, but the sluggish slide movement only occurred with the 10 round mag. My 40c also came with a 15 round mag which caused no issue with slide movement. I noticed that both the 10 round and 15 round mag had the exact same spring (same length and number of coils). Having the same spring in both mags, the longer 15 round mag had significantly less spring tension than the 10 rounder. The 10 round mag has the pinky extension so my grip is effectively the same with either mag. the only real difference seems to be spring tension. That is why I decided to lower the spring tension in the problem mag to more closely match the tension in the longer mag. The only really effective way to lower the tension was to cut out 2 coils. Again, it seemed to work. I definitely want one more range trip before I will be fully satisfied.

 

[saw577]

I bought my wife and I 2 40c's a few weeks ago. We have been training with them, as we intend to carry. The day after I read the initial post, I started to experience the same thing. Its a very weird hang up as the slide moves forward after the shot. Feels very jerky in my hand. We have put almost 1000 rounds through both guns, since we are trying to get comfortable with them before we take a self-defense class this Saturday. Put 165 and 180 gr WWB and Remington UMC through them. Also put some 165 Hornaday Critical Defense through them. We have been using full size 40 mags with the x-grip extension piece, and I have felt the hang up with that mag and the 10 round mags. We went shooting last night, and it seemed to be getting worse with mine, and my wife started to notice it too with hers.

I have noticed alot of wear on the bottom of the feed-ramp, where the bullet nose is rubbing. It also seems my slide spring is not as sturdy. I dont know if that makes any sense. I have 4 other M&P's, all full size, and the main springs on them are very stiff and dont move much on the guide rod. Both of our 40c main springs move, and I dont mean compression. It doesnt sound like sending them back in is going to do me much good, but if it does it as badly this weekend during our class, I may go ahead and see if they can find anything.

 

[xzhync]

I bought my wife and I 2 40c's a few weeks ago. We have been training with them, as we intend to carry. The day after I read the initial post, I started to experience the same thing. Its a very weird hang up as the slide moves forward after the shot. Feels very jerky in my hand. We have put almost 1000 rounds through both guns, since we are trying to get comfortable with them before we take a self-defense class this Saturday. Put 165 and 180 gr WWB and Remington UMC through them. Also put some 165 Hornaday Critical Defense through them. We have been using full size 40 mags with the x-grip extension piece, and I have felt the hang up with that mag and the 10 round mags. We went shooting last night, and it seemed to be getting worse with mine, and my wife started to notice it too with hers.

I have noticed alot of wear on the bottom of the feed-ramp, where the bullet nose is rubbing. It also seems my slide spring is not as sturdy. I dont know if that makes any sense. I have 4 other M&P's, all full size, and the main springs on them are very stiff and dont move much on the guide rod. Both of our 40c main springs move, and I dont mean compression. It doesnt sound like sending them back in is going to do me much good, but if it does it as badly this weekend during our class, I may go ahead and see if they can find anything.

Did you notice the problem right from the get-go or did the guns shoot ok initially? Can you explain a little more what you mean by the slide spring moving. Do you mean that it moves around on the barrel lug?

Hopefully, you will have better luck if you send them back for service. If you do send them back please report back on what they do to address the problem. I took 2 coils off of the mag spring and that seemed to help, but I am going to go out again this weekend to double check.

 

[Beejabbers]

I had a problem with FTF's with my 40c a few thousand rounds ago. I finally decided it must have been a combination of limp wristing and tight manufacture. The pistol almost never fails to feed now and it is almost always the last round in the mag that has to be jacked in. I load all mags with 8 rounds instead of the capacity 10. I was worried at first but not any longer. I have never had a FTF with my Gold Dot carry ammo. Good luck with you 40c, I love mine and only worry about wearing it out at the range.

 

[Coastie762]

Out of curiousity, what do the fired cases look like? Is there any damage to the case mouths on any of them?

If the slide is not travelling fully to the rear due to limp wristing, you may see the case mouths damaged where they contact the front/top of the ejection port instead of being thrown clear. There will also be brass marks on the slide where the cases are hitting.

Also, as the slide did not move fully rearward, as it starts forward the new round may not be fully positioned for feeding, and catch on the bottom edge of the feed ramp.

This condition can be compounded with a full magazine and drag caused by the pressure from the magazine spring as noted above.

Don't ask me how I may know this...

 

[mewisemajic]

I just replaced the recoil spring on my M&P9 FS and I noticed that with a new mag loaded to 17 it will drag the top round in the mag. I did this with a snap cap in the chamber and dummy rounds in the mag. I didn't see it carry over to live fire though.

If it's only happening with the 10rd mag I would say it was a mag problem, not a problem with the 40c itself.

 

[EXERCISINGTHE2ND]

I had over 500 rounds before it started.

Seems to happen after 50 rounds and gun is warmed-up.

Did notice brass marks on the bottom of the slide on the ejection side.

Thought about "limp wrist" and ensured help tight - still felt.

Feels as if the slide comes back, but returns with a "jerking" motion as if 1) something is preventing the slides return and 2) there is not enough spring pressure to return the slide while picking up the next shell because the slide did not go all the way back.

I haven't been to the range since I started this thread so that I could get really good advice as to what to do at my next NRA Range visit.

Thanks all

 

[Mikey217]

I'm having the same issue with my 1 month old 40c. It seemed to happen quite a lot at the range yesterday. I fired 150 rds of American Eagle 180gr through it. Once or twice, it even paused for 4 -5 seconds before travelling the last few cm into battery. It was really weird.

Next time I go to the range, I'm going to do some more thorough testing by marking the mags, trying different ammo, ensuring a good grip, etc. I have 6 10-rd mags that I use, but I only load them up with 5 rds at a time while I'm at the range.

Another oddity yesterday was that almost all of my spent brass was going a good 7-8 feet to my right. Previously, they usually only travel about 3 -4 feet. Following the guidelines in a previous post, I'm going to examine the brass closely this weekend, as well as the feed ramp/ejection port, looking for excessive marks or damage.

I'll update after my next range trip.

 

[xzhync]

I'm having the same issue with my 1 month old 40c. It seemed to happen quite a lot at the range yesterday. I fired 150 rds of American Eagle 180gr through it. Once or twice, it even paused for 4 -5 seconds before travelling the last few cm into battery. It was really weird.

Next time I go to the range, I'm going to do some more thorough testing by marking the mags, trying different ammo, ensuring a good grip, etc. I have 6 10-rd mags that I use, but I only load them up with 5 rds at a time while I'm at the range.

Another oddity yesterday was that almost all of my spent brass was going a good 7-8 feet to my right. Previously, they usually only travel about 3 -4 feet. Following the guidelines in a previous post, I'm going to examine the brass closely this weekend, as well as the feed ramp/ejection port, looking for excessive marks or damage.

I'll update after my next range trip.

For me the problem only occurs with the 10 round mag and is most pronounced when there are 5 or less rounds in the mag. Seems like the mag spring exerts significantly more upward force at that point until the mag is empty. Try pushing rounds out of the mag with your index finger. You will feel that you have to push much harder from 5 rounds down to zero

 

[Coastie762]

I apologize in advance for the length of this post. Hopefully it will make a bit of sense.

I've spent a bit of time at the range this weekend with both my 40 FS and a new 40C. Based on my testing, I now think the hesitation that I've experienced and has also been reported above may be due to the slide stop moving (bouncing) under the forces of recoil and trying to catch in the notch in the slide. This causes the hesitation felt as the slide goes forward. Sometimes it just briefly catches the notch, sometimes it will cause the slide to lock back as if the mag was empty.

The condition was only noted when shooting full power loads and as the mag was partly empty. The partly empty mag provides less pressure on the underside of the slide and a faster slide velocity.

The first time out with the 40C yesterday, the slide locked back early several times when firing full power 180 grain factory loads and heavy handloads. Especially when, as noted above, there were 5 or fewer rounds left in the mag. Light handloads and Privi factory loads (very mild!) ran without problems. BTW these light loads also cycled properly in my 40 FS with a 20-lb ISMI spring installed.

There were no marks on the slide stop to indicate that it was being prematurely actuated by a round in the magazine.

I loaded up some "medium-heavy" 180 handloads and tried them this morning. These loads did not lock the slide early, but I did get the "jerky" slide return, as seen before, after the mag was partially emptied. This was also noted, to a lesser extent with the FS.

If anyone having this problem has access to some lighter loads or handloads, try some and see if your pistol runs smoothly.

The ideal solution would be a heavier slide stop spring, but I am not sure if one is currently available. In the meantime, I'm going to have to buy a spare slide stop assembly to play with and see if I'm on the right track.

 

[xzhync]

I apologize in advance for the length of this post. Hopefully it will make a bit of sense.

I've spent a bit of time at the range this weekend with both my 40 FS and a new 40C. Based on my testing, I now think the hesitation that I've experienced and has also been reported above may be due to the slide stop moving (bouncing) under the forces of recoil and trying to catch in the notch in the slide. This causes the hesitation felt as the slide goes forward. Sometimes it just briefly catches the notch, sometimes it will cause the slide to lock back as if the mag was empty.

The condition was only noted when shooting full power loads and as the mag was partly empty. The partly empty mag provides less pressure on the underside of the slide and a faster slide velocity.

The first time out with the 40C yesterday, the slide locked back early several times when firing full power 180 grain factory loads and heavy handloads. Especially when, as noted above, there were 5 or fewer rounds left in the mag. Light handloads and Privi factory loads (very mild!) ran without problems. BTW these light loads also cycled properly in my 40 FS with a 20-lb ISMI spring installed.

There were no marks on the slide stop to indicate that it was being prematurely actuated by a round in the magazine.

I loaded up some "medium-heavy" 180 handloads and tried them this morning. These loads did not lock the slide early, but I did get the "jerky" slide return, as seen before, after the mag was partially emptied. This was also noted, to a lesser extent with the FS.

If anyone having this problem has access to some lighter loads or handloads, try some and see if your pistol runs smoothly.

The ideal solution would be a heavier slide stop spring, but I am not sure if one is currently available. In the meantime, I'm going to have to buy a spare slide stop assembly to play with and see if I'm on the right track.

You may be on to something. I didn't think much of it, but I also have been experiencing occasional slide lock backs. I thought that was an unrelated problem. Definitely worth some further investigation.

 

[EXERCISINGTHE2ND]

So with the slide issue, I believe my 40c is MD compliant with the internal lock. Could this be any part of the issue and/or something else with the compliant weapons?

 

[Coastie762]

EXERCISINGTHE2ND, None of my M&Ps have the internal lock, so at least in my case they are a non-issue. I have not heard of any firing-related problems traced to the internal locks in the M&P series (unlike the revolver system).

I think the issue is more related to the "one size fits all" system in use for various parts of the M&P platform. Except for barrels and mags, pretty much every other part will interchange between the 9mm, .40 and .357 Sig, caliber pistols. Thats great for mass production; less so for tuning a pistol to different calibers of differing power levels. For example, the same strength recoil spring assembly is used for the above three calibers. Works, yes but probably not optimal.

Midway had slide stops in stock and I needed some other stuff anyway so I've got one on order. There are a few tweaks I want to try to confirm that the problem is actually related to the slide stop. I figured that if I screw it up, I still have the original one to reinstall.

 

[xzhync]

EXERCISINGTHE2ND, None of my M&Ps have the internal lock, so at least in my case they are a non-issue. I have not heard of any firing-related problems traced to the internal locks in the M&P series (unlike the revolver system).

I think the issue is more related to the "one size fits all" system in use for various parts of the M&P platform. Except for barrels and mags, pretty much every other part will interchange between the 9mm, .40 and .357 Sig, caliber pistols. Thats great for mass production; less so for tuning a pistol to different calibers of differing power levels. For example, the same strength recoil spring assembly is used for the above three calibers. Works, yes but probably not optimal.

Midway had slide stops in stock and I needed some other stuff anyway so I've got one on order. There are a few tweaks I want to try to confirm that the problem is actually related to the slide stop. I figured that if I screw it up, I still have the original one to reinstall.

The thing I find curious is if it turns out to be the slide stop then, in my case, why does the slide dragging issue only occur with the 10 round mag and not the 15 round mag?

Do you have both mag sizes? Does it happen with both or just one mag size?

Yesterday I measured the distance between the mag feed lips and found the 15 round mag was over 1/64 wider. I opened up the the feed lips on the 10 round mag and polished the surface. That seemed to make a difference when hand cycling rounds through the gun. I haven't been to the range with this mod, but hope to this week.

I wonder if the spring on the slide lock can be adjusted (tightened)?

I would think that if it is the slide lock, by installing a new one, the problem would temporarily go away.

It is sad, but I think the folks on this thread will solve this problem far faster than Smith & Wesson. When I sent mine in for this problem they polished the feed ramp and replaced the extractor and spring. I am not a gunsmith and I can tell you that their fix is nowhere near the right solution. It really irritates me when they don't even make a reasonable attempt at fixing a problem.

Please let us know what happens with the new slide lock.