M&P 40 Slide Completely Jammed Upon Reassembly

Eric H

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Howdy y'all,

I've spent some time searching for a related issue and couldn't find anything relevant.

Took my M&P 40 shooting today and everything functioned as normal. I took it apart to clean it and everything disassembled normally.

Upon reassembly I've come across this issue. I installed the barrel correctly and the guide rod/recoil spring was installed all the way and centered into the slide and barrel. I go to install the slide onto the frame rails and it passes the the front set fine and I get to the second set fine and then everything on the gun was locked up but I had about a half inch of slide movement but I could not remove the slide.

After trying to get the slide to move and wiggling around the takedown lever the whole gun is completely jammed up. I've got some pictures to show you guys what's going on. It appears that the barrel feed ramp is caught up on the lug where the front rails are. I don't understand how this happened as the spring seemed to be installed correctly. The slide fit on the frame seems proper as well.

The slide is completely jammed up, I can't move the barrel in attempt to free it from the lug. I feel like the recoil spring is jamming everything up. I could use some advice on how to fix this issue, I've assembled this gun many many times and have never had this happen. My son who is also very much into firearms can't figure this out either.

Thanks!

http://imgur.com/11ImaoT

http://imgur.com/gaFMJFr

http://imgur.com/1uzlj09

http://imgur.com/Wn9ERfQ

http://imgur.com/QzvUqOA
 
From what can see... Excess spring pressure on the barrel, which didn't stay seated while reassembly.

I would (with 2 people) try to take pliers and grab onto the exposed guide rod and pull forward, while pulling the frame rearward. Once you have the spring pressure off the barrel have second person try to free the barrel, they may need to hold the slide in place, as it will be trying to move forward at tho time. Will also need to hold open the take down lever too...

Looks like a pain in the backside over all though, In my head I can see how this happened, getting the fix into words, is usually my weak point
 
You put the guide rod in backwards.

You will need to get the sear pin down, then rock the slide back and forth until its slides off the front. Then you can reverse the guide rod intk the correct position and reassemble.
 
You put the guide rod in backwards.

You will need to get the sear pin down, then rock the slide back and forth until its slides off the front. Then you can reverse the guide rod intk the correct position and reassemble.
Don't feel bad...I hate when I do shit like this. It's usually when I'm in a hurry that these things happen to me
 
From what can see... Excess spring pressure on the barrel, which didn't stay seated while reassembly.

I would (with 2 people) try to take pliers and grab onto the exposed guide rod and pull forward, while pulling the frame rearward. Once you have the spring pressure off the barrel have second person try to free the barrel, they may need to hold the slide in place, as it will be trying to move forward at tho time. Will also need to hold open the take down lever too...

Looks like a pain in the backside over all though, In my head I can see how this happened, getting the fix into words, is usually my weak point


I'll have to try this when I get home, thanks!

Wilson911,

The sear pin is that yellow level I would need to push down as in during the manual approved disassembly? I've always done the disassembly in "Glock fashion."
 
From what can see... Excess spring pressure on the barrel, which didn't stay seated while reassembly.

I would (with 2 people) try to take pliers and grab onto the exposed guide rod and pull forward, while pulling the frame rearward. Once you have the spring pressure off the barrel have second person try to free the barrel, they may need to hold the slide in place, as it will be trying to move forward at tho time. Will also need to hold open the take down lever too...

Looks like a pain in the backside over all though, In my head I can see how this happened, getting the fix into words, is usually my weak point


I'll have to try this when I get home, thanks!

Wilson911,

The sear pin is that yellow level I would need to push down as in during the manual approved disassembly? I've always done the disassembly in "Glock fashion."
 
Yes. Sear pin is that yellow wire that must be down.

I had this exact thing happen to me. Getting the pin down and keeping it down while you are rocking the slide is VERY challenging. I used my gf's crochet needle. As long as the sear pin stays down, you should be able to force the slide forward and off. Btw....i used the crochet hook to keep the sear pin down by hooking onto it from below with the magazine removed. Used my left hand to keep pressure on the sear pin while I rocked the slide with my right. If you are left handed, reverse that.

The take down lever should be in the "take down" position too.

Figuring this out was how I frustratingly spent the first night I got my new MP 40.

Good luck.
 
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Wilson911, I'll try what you suggested when I get back home. I remember trying to do this and I could not get access to wire, I'll have to try it again with a flash light.

I appreciate the responses everyone! Reps will be inbound
 
While you are correct that the wrong end will not go through the slide, you are wrong that it cant be put in backwards. The fat end of the guide rod will sit flush in the end of the slide. Then, when you reassemble the fat part of the guide rod will nit push through the hole. That is what is jamming up the gun.

This is not speculation. I did this myself. I also just took mine apart again to confirm.
 
While you are correct that the wrong end will not go through the slide, you are wrong that it cant be put in backwards. The fat end of the guide rod will sit flush in the end of the slide. Then, when you reassemble the fat part of the guide rod will nit push through the hole. That is what is jamming up the gun.

This is not speculation. I did this myself. I also just took mine apart again to confirm.

have you even looked at the photos linked to in the first post?
 
The recoil spring most definitely was not inserted backwards. You can see that from the pictures I posted, I also confirmed it by watching several YouTube videos on the proper reassembly and as far as I can tell from that and from prior experience, I don't think I've done anything wrong. I dont know how it's so hung up. I'll have to try Whatt's suggestion on fixing it.

Any other suggestions or comments pertaining to whatt's "fix" for it? I'd like to see any/all suggestions on rectifying my issue.

Much Appreciated!
 
Eric, I was able to duplicate your situation with the recoil rod and spring removed ( I didn't want to really jam my gun up)

I'm guessing when you reassembled, your barrel somehow became out of place in the slide - the barrel hood was not fully seated in the ejection port while assembling.

It seems if you then pulled the slide rearward, the barrel will become extremely tight where it exits the front of the slide (think barrel bushing on 1911) This is where your jam is. Being that your recoil spring is in place just makes it more interesting to fix.

So, little yellow lever for the sear must be down, take-down lever must be down, relieve recoil spring pressure by pulling the rod outwards to the front (spring may be fully compressed making this impossible) and press downwards on the front of the barrel while pressing the slide far-ward, maybe even drip some oil into the barrel-slide jam area
 
Eric, I was able to duplicate your situation with the recoil rod and spring removed ( I didn't want to really jam my gun up)

I'm guessing when you reassembled, your barrel somehow became out of place in the slide - the barrel hood was not fully seated in the ejection port while assembling.

It seems if you then pulled the slide rearward, the barrel will become extremely tight where it exits the front of the slide (think barrel bushing on 1911) This is where your jam is. Being that your recoil spring is in place just makes it more interesting to fix.

So, little yellow lever for the sear must be down, take-down lever must be down, relieve recoil spring pressure by pulling the rod outwards to the front (spring may be fully compressed making this impossible) and press downwards on the front of the barrel while pressing the slide far-ward, maybe even drip some oil into the barrel-slide jam area

That definitely sounds exactly like what happened. That seems like a very logical fix as well, I'll give this a shot in a few minutes. I tried all of that except for the pliers on the guide rod and setting the sear lever in a down position.

I'll send out a post on the success!

Thanks!
 
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