Need help with new M&P 15-22 misfires

Folks, I need help diagnosing a problem with my new M&P 15-22. And I really want to get it working by April, as my daughter & I were planning to use this rifle for an Appleseed event. We've already signed up.

I’ve only had it a couple of months and have only taken it to the range three times.

The first trip went well. I shot using the 10 round magazine MD requires be sold with the gun in this state. I probably shot 3-400 rounds with only a few problems. I had a 3 or 4 failure to fires (round chambered and was rim-struck by the firing pin but it didn’t go bang.) But I know rim fire is less reliable than center fire plus the ammo I was using was neither on the good nor the bad ammo lists in the S&W manual. So I was happy and didn’t worry about it. Took the gun home, cleaned & lubed it, and put it away for a couple of weeks.

Saturday I took my 14 yo daughter and her friend, a first time shooter. I wanted to make a good impression on the newbie. It was not to be.

The M&P simply would not reliably fire. As before the round chambered, but when the firing pin was dropped we just got the dreaded click not bang. Sometimes round after round acted that way, other times we’d get one round to fire but the next wouldn’t fire.

I was using some new higher capacity magazines that I had gotten while out of state (which I'm allowed to do, for now) and I hoped the problems were mag related, since I had left the original 10 round at home.

So today I went back to the range. It was not the mags. It failed on all mags, including the original mag that once had worked well. Something else is wrong.

I could only establish one repeatable pattern, and even it was not 100%. And that is: If I loaded a mag, dropped the bolt and loaded one bullet, then ejected the mag before I fired, it would (almost always) fire. I could then pull the bolt & lock it back, reload the mag, drop the bolt to load one more bullet, eject the mag again & fire again. Essentially what I have is a single shot bolt action 15-22. Sigh. But if I left the mag in and dropped the bolt, the first bullet would fire, it would eject OK, the second bullet would be loaded into the chamber, the firing pin would drop but it would not go bang. Just click.

When I manually ejected the bullet I could see the firing pin strike on the rim. Yeah some of them might have looked a bit light but others looked almost as big & as deep as the ones fired. (I saved as many of the bullets/shells as I could.)

That was the usual pattern. Occasionally two other things would happen: 1) Once in a blue moon I wouldn’t even get the click. The firing pin was not reset. 2) Also once in a blue moon, it would go into true semi auto mode for short runs before it would eventually fail.

Ammo used was: Federal Champion 36 grains, Winchester Super-X 40 grains , Winchester 555 36 grains (white box), and PMC Zapper. PMC was the one that had the most semi auto runs, followed by Federal, but neither one would always work.

Here are the stats. I logged every shot including which of 3 mags I was using and which ammo. But these are the rolled up stats:

When the magazine was left in:
First round didn’t fire: 1
First round fired, second bullet fed into chamber, firing pin struck but didn’t fire: 23
First round fired, second bullet fed into chamber, firing pin not reset: 3
True semi automatic mode worked successfully, runs of length: 2, 2, 2, 9, 6, 2, 8, 2

When the magazine was ejected after the first round was loaded:
First and only round didn’t fire: 4
First and only round did fire: 28

Below please find photos of the end of some bullets. The first set is of the shells that did fire. The second photo is bullets that were struck by the firing pin but did not go off. It looks like a hard enough hit to me, but what do I know…

Here are a couple of spent brass from my 15-22. I do believe they look as though they have a much better firing pin impact than do those in your photos.



So....first question.....was it cold out today? I ask only because cold temps can cause some lubricants to get thick....and this could cause a weak firing pins strikes if the firing pin is sluggish.

Before I did anything, I would give it another good cleaning and NOT lube the anything to do with the firing pin, hammer, etc. I would leave the fire control group dry for now....and then take it out to see how it works.

Hopefully other will have some more ideas.

Good luck....you've done some good troubleshooting so far.

It was very cold outside today however the gun is stored inside my house, put in a case to get to the car, and was only exposed to the outside air (but inside the case) for less than a minute in the driveway & later parking lot. Great suggestion but that can't be the cause.

I'll certainly try the cleaning suggestions. Thanks.

FWIW, do not put any wet lube in the firing pin channel. The best thing to do is flush the channel with GunScrubber and then blow it out with compressed air. If you absolutely must lube the channel, use a dry lube such as dry graphite.

Too much lube in below freezing temp will often give you the problems you are experiencing. Same deal for the entire FCG. The rule of thumb is, if you can see the lube, you have used too much.

araym said:

It was very cold outside today however the gun is stored inside my house, put in a case to get to the car, and was only exposed to the outside air (but inside the case) for less than a minute in the driveway & later parking lot. Great suggestion but that can't be the cause.

I'll certainly try the cleaning suggestions. Thanks.

Click to expand...

With all due respect, that CAN be the problem. At the very least it will often contribute to it. Warm into cold and back into warm can cause condensation on metal parts. Moisture mixed with lube is not a good combination. All this presumes an indoor range. If the range is outdoor, then you really don't want too much lube.

I hope you get the problem solved quickly.

On the rounds that had firing pin strikes that didn't go off, did you try to fire any of them a 2nd time?

Could it be the way you cleaned it? I was at the outdoor range yesterday and it was 28 degrees. I fired about 250 rounds before it was just too cold on my hands. My 15-22 went straight from 70 degrees indoors to 28 degrees and was firing within about 5-10 mins once it was in the cold. I didn't have a single misfire. The gun fired flawlessly and spot on with the iron sights. I'm using SV CCI and the gun was clean with very little lube residue.

Did you have the FCG out?... If the hammer spring legs are in wrong it would cause the light strikes.... Check your hammer springs... One could even be broken.

Guys,

First thanks again for all of your great comments. They’re very helpful.

But I can assure you that whatever problem I’m having is not temperature or humidity related. My 15-22 was kept indoors, the range was indoors, it was climate controlled in my car, and for the 30 seconds the gun was outside in my driveway or parking lot, it was enclosed in the case. 30 seconds, while protected inside of a gun case, just isn’t enough time to cause a significant temperature or humidity differential. That can’t be the problem.

After listening to all of you I’m leaning toward it being cleaning related. And to underscore that, I note that it worked before I gave it the first cleaning, and after that it hasn’t worked right.

I do have a few follow-up questions for you however. I noticed that several of you suggested keeping certain parts dry of oil (e.g. the firing control group). I didn’t avoid that when I cleaned it. My SOP is to lightly wipe all internal metal surfaces with a LIGHT coating of oil. I’m not talking dripping wet, but I did pass a cleaning wipe that had oil on it across all surfaces including all surfaces of the bolt.

In addition to reading your posts tonight I checked out the YouTube video linked off of the “Notable Thread Index -> Instructional Videos -> How to Clean and Lubricate” links. It surprised me how little brett248vista applied oil. In that video he didn’t lube anything related to the entire bolt group assembly other than the rails themselves. Is that right? There are sliding pieces in here: bolt assembly rails both against the polymer upper receiver sides as well as the bolt itself, spring against the guide rod, etc. Really am I to clean that only and not lube any of the associated parts other than just those internal rails? No light sheen of oil to protect against metal corrosion if the guns sits for a long period of time? (That would be a first for me if so, among all of the guns I currently own.)

And as to the question from Ghost_Soldier, no I didn’t try firing any of them a second time. Good suggestion though. I’ll try that the next time I go to the range. Instead I was trying to save every bullet/shell that I could, in case I needed to take this to a gunsmith. I thought it would help him diagnose the problem. But for sure this is worth checking out, should a another cleaning (with less lube) not solve the problem.

As for the questions from bobermo:
* The bolt and rails do appear to me to slide smoothly. While this is my first 15-22 this isn’t my first semi-auto gun, and nothing out of the ordinary seems wrong with this slide to me.
* I examined my rails and that whole assembly and don’t see any burs or imperfections that I noticed
* The mags seem to load OK. Again I haven’t noticed anything unusual. BUT one problem with the “it’s too much lube” hypothesis is: Why would it work better if I dropped the mag (significantly so) and work worse if I left the mag in? A light strike is a light strike – why would the presence or lack of a magazine change how hard/fast the firing pin impacted the bullet rim?
* The bolt spring is mostly the silver color of the metal but if I look at it from the side I can tell that yes there is a light coating of blue on parts of the spring.

For yugowego: No I didn’t remove the FCG. I just went with the standard cleaning as in the S&W manual. I didn’t even take the bolt assembly group apart, as suggested in the brett248vista video. I hadn’t seen that video yet and was trying to go “by the book” the first time out.

NOTE: As I was just now typing this in and playing with my gun, I checked on the hammer springs as yugowego suggested. The hammer was cocked and I accidentally pulled the trigger so it sprang forward. At that point I noticed the hammer had a bit of a wiggle, and discovered that the pin it rotates around had come loose from the right side! What I don’t know is: Was it that way all of the time, or did I just mess it up by “firing” it while separated from the upper receiver? I honestly don’t know. If the former, perhaps that is the cause of the light strikes? Anyway I wiggled the hammer around and got the pin to realign, and then used a pen to push the pin back into the polymer receiver hole on the right hand side. I was surprised that pin isn’t longer, since it not being flush on both sides contributes to it coming loose. It’s back in now, but I’m going to have to keep an eye on it now to make sure it doesn’t work its way back out again in the future. Really I was also surprised at how freely it moved in the two holes.

So I have two things to try now: a clean (but not lubed bolt assembly group), and a reset hammer pin. Hopefully between the two of these things I’ve solved the problem. Alas I probably won’t be able to get back to the range until next week, but I’ll certainly let you know how things go!

Thanks much for your help and suggestions, and by all means please shoot me some more ideas if something else pops up as possible contributing factors, or if you want to reply to what I said in here.

Thanks again.

araym said:

Guys,


NOTE: As I was just now typing this in and playing with my gun, I checked on the hammer springs as yugowego suggested. The hammer was cocked and I accidentally pulled the trigger so it sprang forward. At that point I noticed the hammer had a bit of a wiggle, and discovered that the pin it rotates around had come loose from the right side! What I don’t know is: Was it that way all of the time, or did I just mess it up by “firing” it while separated from the upper receiver? I honestly don’t know. If the former, perhaps that is the cause of the light strikes? Anyway I wiggled the hammer around and got the pin to realign, and then used a pen to push the pin back into the polymer receiver hole on the right hand side. I was surprised that pin isn’t longer, since it not being flush on both sides contributes to it coming loose. It’s back in now, but I’m going to have to keep an eye on it now to make sure it doesn’t work its way back out again in the future. Really I was also surprised at how freely it moved in the two holes.

Click to expand...

The pins have grooves in them that keep them from moving side to side. The sear/disconnector pin is held in place by the legs of the hammer spring on the two outside grooves. The hammer pin is held in place by a tiny spring inside the hammer, which lands in the center groove of the pin.

If your hammer pin is moving freely then the spring inside the hammer is probably broken. It's been happening a lot lately.

is your bolt fully closing? mine wasnt until i sanded and polished the rails it rides on--it looked like they cut it with a chainsaw really rough and sometimes my bolt wouldnt fully close,this will allow to much head space and out of barrel firing or cause light pin strikes,make sure its not hanging up some where,if so sand the top,bottom and inside surface of the rails

Also make sure you get all the crud out of the little step cut where the round seats on the bolt face. That can cause light strikes as well and it gets pretty grimey pretty quick.

I would contact S&W... I do believe they were having hammer spring problems at some point... It is an easy fix as they will drop a new hammer in it for you... Give them a call or just drop a new budget ALG Defense trigger group in it... Good luck to ya!

The hammer pin sounds like a good bet, but I would still remove all lube from the firing pin area like Majorlk said.
Good Luck!

araym said:

It surprised me how little brett248vista applied oil. In that video he didn’t lube anything related to the entire bolt group assembly other than the rails themselves. Is that right? There are sliding pieces in here: bolt assembly rails both against the polymer upper receiver sides as well as the bolt itself, spring against the guide rod, etc. Really am I to clean that only and not lube any of the associated parts other than just those internal rails? No light sheen of oil to protect against metal corrosion if the guns sits for a long period of time? (That would be a first for me if so, among all of the guns I currently own.)

Click to expand...

As I have posted previously, if you can see the lube, you have applied too much. Other than the bolt carrier rails, there's really nothing that needs lubing in either the BCG or FCG. Any lube applied to other parts, if at all, should be the absolute minimum you can apply. The friction and pressures involved with these moving parts simply don't require lubrication other than perhaps the hammer and trigger hooks.

As for corrosion and rust protection, wiping down the firearm with a silicone rag occasionally is more than sufficient for such protection, unless your house says in the 90 percent humidity range and you leave the firearms laying around. BTW, DO NOT store firearms in pistol rugs and other such for rifles. The lining attracts moisture like a sponge. Even foam-lined hard cases are not a good idea. They all are made for transportation, not storage.

Firearms should be stored in a manner that allows air to circulate around them, consistent with security.

I haven't been back to the range (yet - next week I expect) but I have stripped the gun and cleaned it. I even took the bolt off the rails as in the video and photos in the forum (but not in the manual). Soaked the bolt & blew that whole area out with compressed air. Light oil is now only on the rails - it's no where else on the gun. (Take that back, I used the same wipe to wipe off the bolt spring and guide above.)

Hammer pin is back in position - I'll keep an eye on it. Hammer and trigger springs are inspected - not broken.

On closer examination I did feel a slight bur on the very end of both rails. It seems like they're metal rails with a polymer coating and on the very end a bit of metal is exposed and that seam is not perfectly smooth. I haven't sanded it (yet) but may pull it back out and do that before i head back to the range. It wasn't a big bur, but I could feel it with my finger once I was looking over everything with a fine tooth comb.

Thanks much for all your great suggestions. I'm feeling good that any one of these items could have caused it & with your help I think they're all resolved. I'll let you know...

Follow-up: Is it worth grabbing some sandpaper and buffing this out? It isn't really large enough to easily be visible (hence why I missed it the other day when I gave it a visual inspection) but by the same token you can't miss it if you run your finger over it.

It's right at the very tip of the rail (actually both tips). The rails themselves are otherwise smooth and the bolt itself slides freely.

Worth buffing out or no big deal?

Thanks again.

araym said:

Hammer pin is back in position - I'll keep an eye on it. Hammer and trigger springs are inspected - not broken.

Click to expand...

BTW
The spring I was referring to is inside the hammer. If the pin moves again, that's the problem. It will require you to pull the FCG to inspect it.

Here's some old threads about it.

http://smith-wessonforum.com/smith-wesson-m-p-15-22/284410-hammer-pin-keeps-drifting-out.html

http://smith-wessonforum.com/smith-wesson-m-p-15-22/258121-spring-hammer-fell-out.html

Problem is solved!

I got my 15-22 back out to the range today and I'm pleased with the results.

In my first two magazines I got one failure in each one. But after that it was perfect. By the end of the session I had fired approximately 180 rounds with only two misfires. I cycled through four different brands of ammunition and three different magazines. No matter, past those two early failures it was all perfect.

I even loaded the misfires from the last session. They all shot perfectly as well.

I consider the problem solved. Whether or not it was too much lube near the firing pin and breech area, or whether the hammer pin was detached all along, I don't know. But having addressed both of these issues, my problems went away.

By the way I kept a close eye on the hammer pin to see if it would work its way out again. So far there is no sign that it has moved. But obviously I'll keep a close eye on it henceforth. If it moves again my first recourse will be to call S&W and assume the internal spring is broken. As a backup I'll replace the pin with the locking option discussed above. But so far so good.

Thanks much to all of you who offered suggestions. It was all very helpful to me.

Ray

I'm glad that the problem, whatever caused it, has disappeared.