Please! I just took my Mossberg 500 apart.

[Guns and more]

It's not all bad, but I need some advice from you guys.

My Mossberg 500 is new.
When I load it, everything is fine.
But when I rack the foregrip, two or three shells attempt to jump into the receiver at the same time. Needless to say, none make it to the chamber.

So, I carefully followed the 500 disassembley sticky by Mini-Me.
Wow! have I learned a lot. It's not that hard.
So, there are two bars on the sides of the receiver.
1. The shell stop. I don't think this is the problem because shells stay in the magazine tube.
2. The interrupter. It's purpose is to stop exactly what is happening, prevent more than one shell from exiting the mag tube.

The channels are clean and oiled.

Okay, neither has any burrs or flashing. The interrupter pivots on a pin. when I look at it's profile, it looks a bit bent away from the tube.

It appears that the curved end rides on a shell. When you rack the slide, it moves up or down and allows the rim of the shell to pass, then rides the shell to catch the next rim. How am I doing?

Here's the question. Can I bend it out till it looks flat? It isn't much, but maybe it doesn't take much. Or....could I bend the "finger" that rides on the shell (already curved) a bit more?

My kitchen counter has a bunch of parts on it, but I'm stoked this went so smoothly.

Slould I mention this is a .410?

 

[1KPerDay]

If you so it verrry slowly and look closely at the interrupter, what happens?

Also watch this and tell us what type the interrupter is.
http://www.youtube.com/watch?v=N0xx7-oS2OA

It does sound like an interrupter problem but the shell stop and interrupter work in concert, so if they're both slightly out it can be tricky to diagnose.

 

[RaceM]

Put it back together without the trigger group and lifter in and work the action slowly. You'll need to keep some pressure on the bolt slide or it'll pop out. You should be able to tell then if the interruptor is catching the shell bottom. If it isn't, then yes, it may need a hair of tweaking to the bar, but I wouldn't mess with the hook.

 

[Guns and more]

I bent the interrupter a tiny bit. It's pretty stiff, like it's made from spring steel.
Then I re-assembled everything.
Oh, Boy, I thought I'd never get the trigger group back in! The interrupter fell out a hundred times trying to see inside as to what was hanging up. I looked at every You Tube video, slide forward, slide back, safety on, safety off.Then one time it slid right in.
I tried the action it seems correct, but I tried the assembly with snap caps and it does the same thing. Jams.
If I gained anything, it seems smoother on the action. That doesn't help the problem.

I'll follow up on your idea. See what it's doing.

Also watch this and tell us what type the interrupter is.

I have the newer type, there are no tabs sticking out. If it weren't for the hook and pivot pin, it could lay flat.


Thanks.

Keep em' coming.

it may need a hair of tweaking to the bar, but I wouldn't mess with the hook.

Okay.
As I said above, the interrupter is pretty strong. At first I was afraid I'd break it at the pivot pin, the weak spot. But I could barely bend it. I might try pliers, and make a slight tweak along it's length.

Do you think it would help to keep the tube loaded with dummies, thus compressing the spring?
When it jams, the shells fly out really fast. Like the interrupter doesn't get back in time to catch the next.
I'll take it apart again.

Update: I've been Googling for similar problems, and it seems I'm not alone.
But, I noticed this description,

As the slide moves forward to chamber a round it moves the interuptor out of the way allowing the next round out of the magazine to move rearward slightly until it is caught by the shell stop.

I'm going to watch that very closely. From what I can tell, the shell stop and the interrupter are contacting the shell in about the same place. It sounds like the interrupter should allow the shell to move to the shell stop. There can't be 1/16" difference between the two. I'll watch.
What moves the shell stop out of the way? the elevator?

 

[RaceM]

The shell stop is shoved into its groove by a cam on the left action bar. The interruptor is shoved down by the right action bar/front of bolt slide, and is moved up by the tail of the bolt slide.

You don't want to tweak the interruptor bar any further back than about 1" from the hook. If the tab that rides on the bolt slide sticks out it'll make the lifter hang up.

 

[evan price]

One thing I have seen on new Mossbergs-

The innards are still stiff and not yet worn in. In my experience you need to rack the pump with authority. Racking it too slowly or too gently has in the past caused multifeed malfunctions in some Mossbergs I've seen. The interruptor and shell stop move in a synchronized set of steps triggered by the action bar motion. A new tight mag spring and tight parts in the gun means things are a bit stiff.

 

[RaceM]

Evan, ya beat me to it. While playing with my 500 yesterday I too had a malf on the tube feed as I was slowly racking it. So G&M, once you've got her back together again rack that thing HARD, you won't break it.

 

[Guns and more]

If you so it verrry slowly and look closely at the interrupter, what happens?

Great advice!
The interrupter starts off down and out of the way. The shell stop has the rim of the shell and has about 3/16" on the shell so that looks good. I don't think that will slip off.
As the slide comes back the elevator moves down and gets ready to catch the shell.
Not until the last, oh, two inches of slide travel does the interrupter move near the center of the shell (I don't think it ever is exactly at the center) and then the shell stop moves out of the way....sprong. the shell jumps to the elevator, and as the slide moves away, it's lifted and shoved into the chamber.
Meanwhile, the next shell gets caught by the interrupter until the shell stop returns to hold it.
There is actually about 1/8" between the position of the shell stop and the interrupter. Without a shell in there, I would have said (and I did) they were side by side.

I think the interrupter needs to come out a bit. It's hit or miss if it catches the next rim.
It doesn't look like it ever touches the shell tube. When it does catch the rim, it's by a hair. (1/32"??)

 

[1KPerDay]

Worst case, swap out the interrupter and/or the shell stop... they're relatively cheap. That has fixed the problem in 2 of 3 I've worked on. Or swapping a new interrupter and using the old stop, switching them around until the gun works.

I have had success once carefully bending in the interrupter. Take it out and put it in a padded vise, and carefully adjust the last bit and check function. don't bend it too far toward the middle or you'll cause friction as has been noted above.

 

[Guns and more]

I guess you guys are making me think.
I have a second Mossberg 500 in 12 ga.
So I worked the action very slowly to see if that interrupter worked differently.
That gun works flawlessly. The interrupter bar is perfectly flat.
And the interrupter seems to catch more of the rim of the shell.
I think there's a bit if tweaking in my future.

 

[scallop]

Had the exact same issue with one I bought for my son. The solution to my problems was to bend the shell stop out just a tad. Had to do it a couple times to get it right but function is as intended now. Took me awhile to figure out the problem but after I did it was a "duh!" moment.

 

[Guns and more]

The shell stop catches about the same amount on both guns. In my case, the interrupter seems to be off.
Is it normal for the interrupter to "ride" on the shell as it moves into position? To me that would push the shell over so the shell stop couldn't miss it.

I can't tell on my 12 ga. since the elevator moves up and blocks my view at the last second.

 

[RugerMcMarlin]

Dejavu... I had that on one last fall, My solution was to take it back to Gander, which they quickly refunded. But I really wanted one, I wish now I would have played with it a little.