Mossberg 500 Shell Feed Issue

[Doc7]

I have a thread going on another forum specifically geared towards Mossbergs, but I figured it can't help to get some input from the THR community on this one as well.

I have a Mossberg 500 20 gauge, and shells are sticking on the lip that serves to keep the follower from ejecting out of the magazine tube. This is not an issue with the shell interrupter or the shell stop - as seen in the photos below, I can even get them to stick with the whole gun disassembled except for the tube, spring, and follower.

I have been removing the tube a few dozen times to file a little bit more off of this lip every time (it is smooth all around and I've been hitting it with sandpaper and dowels, taking material off each time as you can see by the blueing removal in the latest photos), but the more I think about it, the more I think that any kind of "straight" lip whatsoever could cause this issue.

Is anyone able to replicate this on their own gun? It doesn't happen every time when I load the gun in the field. However, I can get it to occur 100% of the time if I try (by pushing in the shell and then kind of wiggling it against one edge of the tube so it catches this lip). I'm worried about the times that it will happen when I'm not trying to cause it.

Pic of what the shell looks like in the proper position:



Pic of what I can get the shell to do if I push it into the tube and then wiggle it against one edge of this lip (note that it is about 1/4" away from the shell stop and interrupter bars)



After some filing, here is a picture of the shell still sticking on the lip, this time the gun is disassembled with no stop or interrupter in place - the spring and follower are in the tube in this photo, and holding the shell against that lip:




Thanks for any input on if this happens to anyone else's gun, or if your gun's lip is "beveled" or something to prevent this?

 

[Miked7762]

Common problem. Stop filing!

It's the magazine tube. If it's been overtightened it will be distorted and can catch shell rims itself or the misalignment can cause rims to catch on the receiver. If you are lucky the magazine tube will just be beveled inward. In that case, take a wooden dowel and a hammer to tap the follower out of the magazine, then press it back in and repeat until the lip is smoothed out. If the tube is beveled out or if it has wrinkled you're either going to have to try your luck at reshaping it or just replace it.

 

[Doc7]

Common problem. Stop filing!

It's the magazine tube. If it's been overtightened it will be distorted and can catch shell rims itself or the misalignment can cause rims to catch on the receiver. If you are lucky the magazine tube will just be beveled inward. In that case, take a wooden dowel and a hammer to tap the follower out of the magazine, then press it back in and repeat until the lip is smoothed out. If the tube is beveled out or if it has wrinkled you're either going to have to try your luck at reshaping it or just replace it.

Not quite sure that I understand your suggested repair plan. When I unscrew the mag tube, the spring and follower pop right out of it. What do you mean by tapping the follower out? Additionally, the only way a dowel can go into a 500 tube is from the threaded end that goes into the receiver; there is only a small threaded hole at the other end (not a cap like the 590 model that comes off).


Additionally there is a data point to consider that I think makes blaming tube distortion questionable. I really appreciate your reply but I would like your thoughts on this: This problem only occurs on the final shell that I hand load into the tube. IE, if I load 2 or 3 shells, here are the only outcomes I've observed:

1) the first shell hangs up because I intentionally cocked it against that lip for testing purposes to see if that still happens. Wiggling it sets it free and I can rack and chamber all 3 shells in order with no issues.

2) the first (last one loaded) shell hangs up unintentionally (50% of the time). Wiggling it sets it free and I can rack and chamber all 3 shells in order with no issues.

3) all 3 rack and chamber with no issues.


Does the fact that shells beyond the last one I loaded feed reliably make any difference in suspected causes here? Thank you...

 

[nulook45]

Common problem with mossburgs replace the magazine spring its weak and letting the rim of the shell hang up screw the tube in hand tight replace the spring and follower they should slide thru to the cartidge stop .

 

[Doc7]

I really hope this ends up as simple as replacing tube or spring. The problem can be replicated no matter how many shells I put in the tube, if it was a weak spring wouldn't the fifth shell be causing the spring to be compressed enough to overcome that if it was the only problem?

 

[Tolkachi Robotnik]

Last shell more side torsion.

As you put more shells in, the linear arrangement of the spring is perhaps compromised. It will wiggle or force the shell to one side more than if there were just two in the tube magazine. It may well be repaired with a stronger spring as stated above.

In general, a Mossberg I have will hold more shells than it will feed. It handles the usual two just fine. I would say it is due to non-linear arrangement of the spring when squeezed all the way down. You might be able to change how it works by turning the spring around if one side of the spring has a denser coil.