Mossberg 500 feeding/cycling question - Solved

[m102404]

I haven't had a lot of trigger time on this one. I may not have all the shotgun parts terminology bang on...bear with me.

Mossberg 500 Cruiser
- new
- <20 rounds through it (#8/#4/00)
- functioned 100% the 1 and only time I took it out at the range (just bought it)

Situation:
- "dummy" loaded with [forget the brand] red aluminum snap caps
- loaded 5 in the mag, 1 in the chamber...doesn't seem to matter the symptom seems to come up randomly with any shell in the mag

Symptom:
- slowly/"short" racking the slide may result in a failure to load (i.e. shell in chamber pops out, shell in mag may not pop out into the lifter)
- "gently" racking the slide (i.e. not slamming it all the way back)...the shell in chamber will eject 100%...the next shell in mag may not pop out into the lifter. This is (as far as I can tell) random. Full mag, last shell, anywhere inbetween. It will result (if I don't hear/see the shell pop out) in an empty chamber.
- rapidly/hard racking the slide (i.e. loud enough to piss off the wife) will result in proper feeding...although it might not (hard to judge if I'm racking it back with the same/"enough" force each time)
- I can short rack the slide to where it's almost all the way back (to do an administrative unload of the chamber) and pick out the shell...and most times completing the rearward rack will pop the next shell into the lifter.
- All in all...working the action normally (i.e. like normally working the action of other pump shotguns)...the failure to load the next shell is about 5-10%.

Note: after getting an empty chamber and a dead-click...giving it a really good hard jacking of the slide will usually get the next shell to pop out and feed.

Observation:
- the "leg" that holds the shells in the mag seems to position itself a bit randomly with each shot. Sometimes the "foot"/tip of it will be further in to the center of the shell...other times more to the edge. Seems like when it's more to the edge the shell will pop out and fall into the lifter more reliably without having to rack the slide "violently". Every time it's failed to pop out a shell into the lifter the tip of the bar that holds the shells in seems to be positioned further towards the center of the shell.

Question(s):
- is this sort of feeding normal? (I wouldn't expect so)...when actually shooting (i.e. recoil) does that type of behaviour "go away".
- should you be able to firmly but not violently rack the action and have it feed properly? ....or MUST you rack it really hard/fast (don't expect so)?
- has anyone else experienced something similar? Was there a resolution?
- for my own clarification....what part of/in the shotgun moves the "foot/leg" of the bar out of the way to allow the next shell to feed? Is it the edge/width of the lifter swiping it as it moves down? Is it some other cam/bar/peg/notch?

Any help/observations are much appreciated.

Thank you.

******edit********
Solved - see post #12 in thread

 

[Jarlath]

Are they the plastic rim snap caps? Those are notorious for hanging up in anything that has a "catch" for the rims.

You would be better off using spent shotgun hulls with recrimped ends or even cut off the expansion section.

If it is with metallic rimmed snap caps, I'm stumped.

 

[m102404]

I have just a couple of spent shells...I'll fold them back up and see.

The snap caps I have are 1 solid ?aluminum? piece (with red anodizing/colour) and a ?rubber/plastic? plug for a primer.

 

[Wild-Wild-West]

Hey there m102404!

I had the same problem as you with a 500AB I bought back at the beginning of this year. I bought it used (and it was "very used!") However, mine would not feed at all. It appeared that the "shell stop" on mine was bent to the point that it would not feed at all!

However, I did a search and found this article:
http://www.thehighroad.org/archive/index.php/t-185095.html

I adjusted my shell stop, and it would occasionally feed. So, I measured the captive edge of my shell stop, and filed it down with a small fine tooth file (as per the article.) Do this very slowly and check the shell stop often after only a few strokes of the file!!! If you take too much off, you'll have a very difficult time putting it back!!!

After filing and fitting my shell stop, my 500 feeds like a charm, and no problems thus far.

Hope this helps,

w.w.w.

 

[supernova]

M102404, Did you dissassemble the shotgun to clean it? The cartridge stop and interuptor are a PITA to put back in on a mossberg 500. Ive got a maverick 88 cruiser (blued steel version of 500) and it eats whatever shells I feed it. I'm wondering if the cartridge stop or interuptor wasnt reinstalled properly and is moving around a little bit. And yes, the lifter is swung down by the bolt which pushes the interuptor/stop outward, allowing spring pressure in the mag tube to feed another shell onto the lifter. I have over 100 rds. through my maverick without one single problem, but it did take some time to figure out how to properly install the interuptor and stop. I took a pic of the stop holding a shell back for you to compare with yours. Note that it is always in that same position until the lifter pushes it back on mine, there is no play in it whatsoever, and my maverick couldnt care less what force I use to rack the action, it just keeps feeding and firing rounds until I run out. As mentioned above, it could also be the dummy rounds as they are plastic. I hope this helps and let us know if you have any more problems.

 

[m102404]

Thank you both...I'll read through that link and check that out.

I have taken the barrel off....but nothing further.

Most times the cartridge stop is positioned like yours is in the picture...other times it's into the "R" of Remington in the pic (which seems too far and out of place).

I'll have a chance to do some headscratching and another look at it tonight.

Thanks again

 

[supernova]

M102404, I had a good look at mine and the cartridge stop is held firmly in place as in the picture, it doesnt move outward towards the center of the cartridge base. My geuss is yours either got bent somehow or is loose. It may just need to be taken apart and reassembled. Let us know how it goes

 

[m102404]

I wanted to get some more "pre-fixed" use before I started modding anything....and got to put roughly 2 boxes total +/- of a mix of #8/#4/#2/#00 (need a proper stock...that's a lot of pistol grip only shooting). 2 (maybe 3) failure to load where the shell didn't pop out of the mag. Functions 100% otherwise.

This week I'll get into it and take a good look at that specific part. I strongly suspect now that either bending it back a bit and/or filing the tip of it will do the trick. I'll likely file the tip so as now to end up with a weirdly bent bar.

BTW....as an aside. My buddy had his 14" Norc 12g there to compare. The feeding/cycling is much much rougher (but still fun). His cartridge stop point of contact is absolutely minimal...looks like half as much as the pic and it actually looks bent so just the corner is touching the shell rim. With 4 in the mag he has problems with it spitting out 2 shells, then it works fine. He's going to check his out as well.

 

[brybenn]

Pumps r designed to b racked hard and fast. If the gun is new the mag spring may b overly tite causing more friction on the interupter. Take it skeet shooting n rack hard it'll work its self in

 

[Boomer]

Pumps r designed to b racked hard and fast. If the gun is new the mag spring may b overly tite causing more friction on the interupter. Take it skeet shooting n rack hard it'll work its self in

Yup, you should work a pump gun like you mean it. You won't break it, feeding will be reliable with good quality ammo, and it is important to develop muscle memory to prevent short stroking the action at an inconvenient time. Loading and cycling drills are an important part of your practice and training, so as others have said try to locate some inert ammo that has a metal rim and a shot load that duplicates the weight of a live round. Provided your gun is working properly, both the shell stop and the shell interrupter work at a precise point in the cycling process. There should be no round to round variance, although as previously posted, it is possible that your snap caps are hanging up.

 

[gyates93]

If the gun is brand new, there's a good chance that the shell stop/interrupter could be gunked up with some dirt/packing grease/oil, causing it to need to be given the good hard push to get it to function properly. I'd try to take it all apart and clean it first. If you're worried about not getting it back together let me know, I'll try to take some high quality pictures of how they fit into the gun.

Unfortunately, the reassembly process of the Mossberg/Maverick is the leading cause in the evolution of a third hand for their owners.

 

[m102404]

Quick Update and Problems/Issues Resolved (Yeah!):

- after a couple of range trips I definitely confirmed that even with live firing (recoil, etc...) the shotgun would fail to pop the next round into the lifter about 1-3% of the time. Brand, type, load, etc... of shell doesn't matter (all 12g, 2 3/4", variety of shot/buck/aluminum dummy rounds).

Resolution:
1. I ground the very tip of the pointed tip of the shell interupter/retainer (flipped upside down, barrel pointed away, looking down into receiver...the bar on the right side). I ground it about 1mm "straight" in line with a long axis of the magazine tube.
- this did not resolve the issue...still failed to feed periodically...if not more
- disassembled and reassembled...no change

2. I took the lifter out of the receiver and (again with the parts oriented as if the barrel was pointed away and the shotgun flipped over upside down) just slightly bent the side/wall/arm of the lifter that contacts the shell interupter bar outward a bit. It's a tough thick piece of metal so it takes a fair bit of controlled force to do so. I made the adjustment at the saddle/cup part of the lifter...not on the leg/arm of the lifter.
- prior to making any adjustment, I very slowly/gradually watched the lifter/retainer interact as the action was cycled. I could see how the tip/foot of the retainer wasn't quite clearing the edge of the shell all the time (the little bit of play/position of how the shells sit in the mag tube probably made the difference)...almost but not quite sometimes.
- post-adjustment the lifter went in much tighter and I was worried that it was going to jam going up and down. Working the action a dozen+ times got it going nicely.
- carefully watching the two parts interact relative to the shell head/rim post adjustment I can see how the retainer is now fully pushed to the side out of the way of the shell when the slide is fully retracted.

Final obsevations:
- feeding is 100% now...pumped slow, fast, hard, soft.
- doing an admistrative round substitution (ie. swapping out the chambered shell for the next one in the mag tube) is much, much more reliable since the shell can be picked out of the chamber and the final little movement of slide will reliably pop the next shell out into the lifter. The lifter doesn't drop until the slide is almost all the way back, just barely before the action is fully to the rear and ejecting the shell...a little awkward but ok.

Thanks for all the help and pointers guys!