Buttstock threads stripped?

[MarioB]

Hi y'all,

 

I've had my M4 for maybe a couple of months now and was looking into getting a collapsible stock, as the model I purchased came with the fixed stock. 

I found out that the collapsible stock only works with a certain kind of buffer tube and so I decided to see if that was something I would also need to look into getting.  The stock came off easy enough once I removed the trigger assembly, and good news is: I have the right buffer tube.

The bad news: as I was putting the fixed stock/pistol grip back on I was under the impression it would only fasten back to the functional position. So eventually it started to have a good amount of resistance but it fastened past alignment with where the trigger should be and I assumed it needed another turn. As I was giving it that last turn I heard a plastic snap and the stock came off. It doesn't seem like I broke any small parts loose, but now it doesn't to want to fasten at all. 

Now I'm not a big guy and I wasn't using a vice or any kind of tools that could potentially be viewed as excessive for my purposes, but what do you all think? Broken/defective? Broken/ I'm an idiot? Not broken/there's a trick to it?

Let me know, I'm open to all suggestions. Like I said I was planning to buy a different part, but it just sucks to think the stock buttstock didn't survive one disassembly

 

[MarioB]

The threads on the buffer tube seem fine by the way

[Ben elLes]

Probably have to pick up a new one. Sounds broken.  You just put it on there till you feel some resistance and the trigger guard keeps it from spinning.

[MarioB]

1 hour ago, Ben elLes said:

Probably have to pick up a new one. Sounds broken.  You just put it on there till you feel some resistance and the trigger guard keeps it from spinning.

RIP. Well I guess I know for next time.

Out of curiosity though, what do the threads inside the stock look like?  I imagine there can't be too many.

[Ben elLes]

1 hour ago, MarioB said:

RIP. Well I guess I know for next time.

Out of curiosity though, what do the threads inside the stock look like?  I imagine there can't be too many.

Guessing that you are referring to the 3 position stock?  It’s the same thing but just a handle.  The butt stock slides on a pin that fits in the grooves of your buffer tube

[MarioB]

12 hours ago, Ben elLes said:

Guessing that you are referring to the 3 position stock?  It’s the same thing but just a handle.  The butt stock slides on a pin that fits in the grooves of your buffer tube

No no, sorry. I meant inside of fixed stock. I'm trying to figure out what broke specifically. I assume there were reciprocating threads for the ones at the top of the buffer tube, but there's no trace of them on mine. Pics attached for what their worth. 

I'm still holding out hope I could buy a relatively cheap part to make this thing serviceable again but I have no idea what's missing. It's one of those things you never stop to think about until it fails on you haha

[Ho-bert]

looks like the threaded plastic insert is sill on the recoil tube?

 

[StrangerDanger]

Here are the components inside of the stock. The threaded end on the right screws into the bottom of the receiver extension. There is also a plastic guide loop that the center shaft goes thru. I'm wondering if it may have broken and is allowing it to move around.

I'd want to remove the buttpad to take a look to see what kind of movement is present in the assembly. If you don't want to deal with any of that, Benelli will likely warranty the stock for you.

 

[MarioB]

1 hour ago, StrangerDanger said:

Here are the components inside of the stock. The threaded end on the right screws into the bottom of the receiver extension. There is also a plastic guide loop that the center shaft goes thru. I'm wondering if it may have broken and is allowing it to move around.

I'd want to remove the buttpad to take a look to see what kind of movement is present in the assembly. If you don't want to deal with any of that, Benelli will likely warranty the stock for you.

 

I'll see about getting under the butt pad tomorrow, I probably don't have the right screwdriver for the job.

 

When you say it screws into the bottom of the receiver extension, you mean that thing I've been calling a buffer tube right? I haven't checked in there yet since I didn't wanna fool with the snap ring or the spring, but I think you may be onto something there

[StrangerDanger]

The screws for the buttpad are a philips screw. Put some oil on the driver and it will push into the two holes on the buttpad. Then you just have to feel your way around until the driver engages the screw. 
 

Correct on the receiver extension being the recoil tube. This disassembly guide I made a few years ago might help lead you thru some of the inspection. These assemblies are a pain in the ass to take apart, but it is doable. However if the polymer ring that is molded into the middle of the stock that aligns the center bolt is broken, it may be trash. 
 

 

[MarioB]

1 hour ago, StrangerDanger said:

The screws for the buttpad are a philips screw. Put some oil on the driver and it will push into the two holes on the buttpad. Then you just have to feel your way around until the driver engages the screw. 
 

Correct on the receiver extension being the recoil tube. This disassembly guide I made a few years ago might help lead you thru some of the inspection. These assemblies are a pain in the ass to take apart, but it is doable. However if the polymer ring that is molded into the middle of the stock that aligns the center bolt is broken, it may be trash. 
 

 

I checked that out, and I'm not gonna be able to get past the loctite. Inside the receiver extension though, the stock retaining screw's inner threads are looking pretty stripped. I can tell they are/were there but they aren't substantial enough to cast a shadow. I'd suspect the rest of them is still wrapped around the stock's stay bolt.

 

It'll be a bit longer before I can take a closer look, so I went ahead and reached out to Benelli support. Hopefully I'll hear back from them in the next few days.

[StrangerDanger]

Probably the best route since that stock retainer screw is like 40+ dollars these days and the stock itself might be damaged as well.

 

Definitely a weird failure. 

[MarioB]

Update for anyone still following:

 

Talked to tech support today and they said if I didn't remove the stock retaining nut/washers/stock stay bolt prior to taking the stock itself off, I've voided the warranty.  Doesn't seem right to me, but very typical. I do plan to dispute that, so we'll see how it goes. I checked through my manual again and confirmed it says nothing of the sort. 

 

In hindsight, this isn't the first, and probably won't be the last time I void a warranty following YouTube tutorials

 

[StrangerDanger]

Have you taken the sling assembly out of the stock previously?

I'm not understanding how you voided your warranty.

[MarioB]

40 minutes ago, StrangerDanger said:

Have you taken the sling assembly out of the stock previously?

I'm not understanding how you voided your warranty.

Nope, never. I don't understand either, to the point that I question the rep I spoke to's technical knowledge on the subject.

I won't name names, but there are licensed Benelli dealers on YouTube instructing that it's done the way I did it. Not that that makes my case, but I feel justified in pursuing the matter further. 

If they won't warranty it, it'll just be cheaper to buy the replacement part and fix it myself, and in the interest of saving a buck I'm prepared to go that distance. The only thing I'm uncertain of is how I'm going to get a heat gun on that stock retaining nut without melting the stock itself.

[StrangerDanger]

I'd call back and try to get someone else on the phone. It seems like they didn't understand your issue. Hopefully they'll just be willing to replace the stock and send you a new one.

[MarioB]

Now that I've had a chance to get in here and break it down. The threads on the stock retaining screw are fine.  I think what's happening is whenever the screw comes into contact with the stock stay bolt, it's threading further into the receiver extension instead of interlocking with the stay bolt. I backed the stock retaining screw out a bit, put back in the snap ring and the stock started tightening back on again.

 

Is there a sensible way I can secure the stock retaining screw towards the end of the receiver extension that won't come back to haunt me?

[benelliwerkes]

On 8/2/2022 at 8:14 PM, MarioB said:

I won't name names, but there are licensed Benelli dealers on YouTube instructing that it's done the way I did it. Not that that makes my case, but I feel justified in pursuing the matter further. 

 

Prior to my posting many years ago describing the fastener system for the Benelli M4 fixed stock, and its disassembly / assembly I never saw any YouTube on the topic....share the Link(s) for Benelli Dealers or it didn't happen.

Edited August 9, 2022 by benelliwerkes

[StrangerDanger]

On 8/6/2022 at 11:22 AM, MarioB said:

Now that I've had a chance to get in here and break it down. The threads on the stock retaining screw are fine.  I think what's happening is whenever the screw comes into contact with the stock stay bolt, it's threading further into the receiver extension instead of interlocking with the stay bolt. I backed the stock retaining screw out a bit, put back in the snap ring and the stock started tightening back on again.

 

Is there a sensible way I can secure the stock retaining screw towards the end of the receiver extension that won't come back to haunt me?

This seems odd. Anytime I install the stock retaining screw, I screw it all the way into the bottom until it stops. Never had any issues with stocks not being able to grab the threads and tighten itself up. 
 
I’m thinking the threads on the stock stay bolt may be stripped off the end. 

[MarioB]

@StrangerDanger you could very well be right about that. As far as my understanding goes the whole ordeal was essentially sorcery. I put a few drops of thread locker on the stock retaining screw and placed it back with just enough room for the snap ring to place as well. Idk if that was the source of my issue, but it seemed like it helped to hold in place for the purposes of reattaching the fixed stock. 

Also the collapsible I ordered off gun broker came in, so it'll just be sitting with the rest of my spare parts, hopefully never needing to be used again.

 

@benelliwerkesi didn't mean to call anybody out, I was just in a pinch looking for a way out