HELP, ejecting issue with my full size .40 destroying brass

[Rocker665]

Hey guys for some time now my m&p 40 has been destroying brass upon ejecting the spent brass, it seems to be return to battery before fully ejecting, out of the hundred couple rounds I shot trying to figure this out maybe 10 didn't get destroyed and 1 actually jammed you'll include photos if I can figure out how to post them,
The gun **** great had about 2k rounds through it Nd then started, it had just night sites and a apex duty carry kit in it at the time, I proceeded to replace the guide rod assembly figuring it may be worn out, no luck, then when I got fed up I ordered everything I could minus the seer block, as the gun sits now it has the trijicon night sights, apex duty carry kit, the upgraded reset ram under the rear sight, the failure resistant extractor, AEK trigger, and I also replaced the ejector that sits on the seer block, I'm clueless as to what else could be cause this anyone have any ideas?
It has done this with multiple types of ammo, hollow points FMJ, all different brands,all ammo shot normal out of my friends m&p and did that in mine.

 

[armorer951]

I would suggest the gun is not able to open fully, and the slide is closing on the brass, because it has not been pushed out of the breech area by the ejector. (sorry to state the obvious, I'm sure you are aware that this is the crux of the problem) You should, however, see a definitive ejector mark on the back of the casing. No ejector mark, or one that is very faint would indicate the ejector is not forcefully impacting the rear of the casing as it should be. (Slide velocity too slow)

The other dent on the case mouth (the smaller one, on the left side in image #2) seems to also suggest that the casings may be hitting the bottom of the ejection port in the slide as they are being forced out by the ejector. Is there an obvious deposit of brass on the bottom ledge of the ejection port after you have finished firing? If so, the casings may be impacting that area and then bouncing up into the path of the slide as it is closing. Does the slide always lock back (lock open) on the last round? Would it be possible to have someone watch the area of the ejection port while the gun is being fired?

Perhaps the recoil spring or spring assy is too heavy? Magazines may play a roll in this also. Just some ideas.

 

[adrianolsen]

1. Your recoil spring end should be colored yellow 2. Your ejector should be straight 3. Reset ram? If your talking about the striker block, you might have kinked the spring. To check, push down on the striker block- should not be crunchy and should go flush with the bottom of the slide channel

 

[ExcitableBoy]

Most likely the recoil spring is too stiff, thus causing the cycling to be too quick to eject the spent casing. I've seen this effect a number of times with "improved" semi-autos of all kinds, including rifles and shotguns.

The most recent example of this I have dealt with was with a Remington M48 shotgun (Basically a Browning A5 with a recoiling barrel and recontoured receiver) that I picked up cheap. The barrel and butt stock had both been roughly chopped to create a "whippet" gun. When test firing in this configuration, shells would fire just fine but would fail to eject, and darned near rip the rim from the casing, but leave the shell firmly lodged in the chamber. After flipping the friction ring around and giving the M48 a good cleaning and lube, the problem still persisted.

It took a bit of thinking, but I finally figured out that the mass removed by cutting the barrel was needed to cycle everything at the correct rate. Instead of cutting the recoil spring or replacing the barrel (anywhere between $135-$200, if you are lucky enough to find one), I cleaned up the hacksawed muzzle with a good tubing cutter, smoothed everything out, and made a heavy steel collar with a stout sight blade, then sweated it on over the last 2 1/2"-3" of barrel. For good measure, I also installed two allen-head set screws on the underside to keep the collar in place on the hard-recoiling puppy.

Voila!!! Problem solved. It again shot like a dream... except for the fact that I damned near bloodied my nose when firing it from the shoulder with the super-short stock! I corrected that problem by making and fitting a chunk of black walnut and installing a new Remington Super Cell pad.

The Lesson: Every time you monkey with something engineered by the factory, it is reasonable to expect that things will not turn out perfect. You must know how one part will affect the other, and switching out parts on a wholesale basis is almost always a bad idea. Unless you have done a particular build before and have worked out all the bugs, it is best to swap parts one at a time and test as you go.

It is wayyyy easier to iron out any kinks when following this friendly guideline.

 

[Kiwi cop]

Slide cycling too fast, not too slow. Increase recoil spring weight.

I had this problem with one of my .45acp 1911’s. When shooting full power loads the last round would catch on the case mouth which would be jammed on the chamber mouth with the case base still held by the breachface area.

The problem was the light factory (about 9 Ib) recoil spring in the pistol. When there were rounds in the mag the slide would move slowly enough under the upward pressure of the round to give time to eject the case. With no subsequent round to put pressure on the slide to slow it down the slide would slam forward so fast the case did not have time to eject.

Installing a 14 Ib recoil spring (standard for 230 gn full power .45 ACP is 18 Ib). the problem was cured and lighter powered (120 PF) rounds still functioned

I suspect your spring kit has a too light recoil spring. This happens when people think “lighter spring and faster slide is better”. In fact a heavier spring slows down the rearward travel of the slide allowing time for the case to eject, and less muzzle rise as the spring absorbs the impact of the slide reaching its rearward travel, coming to a halt before moving forward again. There are some YouTube videos showing how slowing down the slide actually reduces felt recoil and muzzle rise.

Try putting your original recoil spring back into the pistol and see what happens. If it cures the fault try a spring weight half way between the two and repeat until you find the lightest spring that functions properly in your pistol.

 

[swsig]

This is a long shot, but could you have encountered a batch of bad or weak ammo? I've had failures to eject from weak ammo failing to cycle the slide with a couple of my semi-autos, though not with my M&P 40c. It has 12,500 rounds through it, with maybe 2 or 3 FTEs. If your FTEs have occurred with a variety of quality ammo, then a mechanical issue is the likely cause. If that is the case, Smith & Wesson will take good care of you. My 40c developed light strikes around 10,000 rounds. When a new striker did not cure the problem, S&W took it back and rebuilt it good as new at no cost to me. Turnaround was 3 weeks.
Good Luck!

 

[Coastie762]

I think Kiwi Cop is on the correct path, I've seen the same issue with my older .40 FS.

OP has a full size .40, factory springs for both the 9 and .40 FS were originally color coded blue. Yellow is used in the compacts.

S&W also made a stronger full size spring assembly for the full size, color coded green for use with .357 Sig (or so I had been told). I recall reading that later .40 FS pistols came with a green coded RSA but that may just be my old man brain misfiring.

My FS .40 came with the blue spring; I also saw occasional cases showing the same damage as displayed by the OP, also with .357 Sig cases when using a factory .357 barrel with the blue RSA. My first thought with my problem was an extractor issue. I installed an Apex Failure Resistant Extractor but saw no change in performance.

Installing the green RSA in my .40 FS resulted in smoother operation with both .40 as well as .357 Sig.

I'd recommend trying the green coded RSA and see if that improves function. Keep the blue spring and use it for reduced power loads or if you install a 9mm conversion barrel.

 

[Rocker665]

I did buy a original replacement spring the same weight as the gun came with I thought mine was worn out when it started crushing the brass, but it did it with both of them I did consider going down on the spring weight, keep in mind too this gun crushed the brass with ONLY a apex trigger kit and night sights, and I returned it to factory trigger and tried it and it still crushed brass, I only added all the other parts because I figured if I'm gonna replace everything I mas well upgrade them and the ram I was talking about is APEX tactical Reset Assist Mechanism, R.A.M., the gun seems to fully function normal except for the spent casings hitting the top front of the ejection port on the way out ill try ordering another recoil spring this time a lighter one

 

[Saudade]

OK wait. You first said the ram was under the rear sight. That would be the striker block. The APEX RAM goes in the Sear Housing and is designed for the models that had the internal lock. So which is it?

Who installed the parts?

Make sure there's no junk or debris under the extractor. Did you replace the Apex one with the stock one too?

 

[ScaryWoody]

I would say it's the extractor. If you have 2000 rounds through the gun the extractor may have debris or needs replacing.

 

[Retired Cop]

Put the factory recoil spring back in the pistol!

 

[rsrocket1]

You also replaced the ejector that sits on the sear block, something may be happening there. Try to replicate the problem by chambering an empty case with a dummy round in the magazine. Slowly pull the slide back and see when the case ejects out the side if it does at all.

 

[Rocker665]

Apex failure resistant extractor and I installed all parts, I did them some time ago now this happened go the pistol about a year ago I just threw it in the save and forgot about it bacl them but I could if sworn I had to take the rear sight off to install the Reset Assist Mechanism... could be wrong like I said it's been a while sense I installed them

OK wait. You first said the ram was under the rear sight. That would be the striker block. The APEX RAM goes in the Sear Housing and is designed for the models that had the internal lock. So which is it?

Who installed the parts?

Make sure there's no junk or debris under the extractor. Did you replace the Apex one with the stock one too?

 

[Rocker665]

Every part of the gun besides the frame and slide, seer block, and barrel is brand new I've replaced every thing else, ejector and extractor were the seclnd thing I replaced first being guide rod and spring assembly

I would say it's the extractor. If you have 2000 rounds through the gun the extractor may have debris or needs replacing.

 

[Rocker665]

I tried multiple springs including ones from friends m&p 40 pistols

Put the factory recoil spring back in the pistol!

 

[Rocker665]

I've tried from everything I see it cycles fine, that's why I think it may be returning to battery too fast, I ordered a lighter recoil spring we'llsee if that helps when it comes In

You also replaced the ejector that sits on the sear block, something may be happening there. Try to replicate the problem by chambering an empty case with a dummy round in the magazine. Slowly pull the slide back and see when the case ejects out the side if it does at all.

 

[FloridaS&W]

The gun has a lifetime service warranty; instead of all this guess work you might consider just sending it in to S&W for service.

 

[ScaryWoody]

I thought I'd google around for an answer. I came across this thread Link

Rocker665, looks like you started that thread 5 years ago. Same issue?

 

[swsig]

I thought I'd google around for an answer. I came across this thread Link

Rocker665, looks like you started that thread 5 years ago. Same issue?

Good sleuthing! I wondered why he hadn't sent it back to S&W, but after reading the posts in the old thread, I saw that he may have gotten some advice that could have scared him off. One of the posters told him that if he sent back his gun with the Apex parts, S&W would remove those parts, install factory parts in their place, keep the Apex parts, and charge him for the new factory parts. Maybe that was true in 2013, but I had a different experience when I sent my 40c in for an overhaul last year. My gun had an Apex DCAEK installed, but S&W not only returned the Apex parts, they did not charge me a cent for rebuilding my gun. My advice is that he should call S&W customer service to discuss his case, and find out in advance if he can get free repairs and his Apex parts back.

 

[Retired Cop]

Changing parts in a S&W firearm, voids the warranty, creates operational problems and can create some real serious problems in a court of law if you ever have to use a modified gun! Just saying !!!!!!!!