Mossberg 500 Action Jams


November 25, 2007, 07:24 PM
I have a single action bar Mossberg 500C 20 ga. About every 3 or 4 rounds the action will jam upon chambering a fresh round. Requires removal of the barrel to
clear, then you can pump or fire 3-4 more and it will occur again. This is not a pure extraction issue or feed issue. The action is physically jammed. Yes the gun is clean and lightly oiled, before you ask. This condition occurs whether firing or cycling cartridges through the chamber.

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November 25, 2007, 09:00 PM
It won't extract the unfired round? If so, I'd think the extractors may need attention. It would be an extraction problem. Or, the chamber may have corroded or something.

If I'm using Winchester Dry Lock or Xpert 3" steel, occasionally mine'll stick after firing, fail to extract. I know of one other person complaining about this and an 870 shooter. Seems to be a problem with Winchester's steel shot ammunition of some kind. I know of no other ammo that has this problem.

November 25, 2007, 09:53 PM
This is does not seem to be a cleanliness or ammunition corrosion issue, you can feel a difference in the forward motion of the slide when this is going to occur. The Round is NOT stuck, else the barrel would be stuck and it is easily removed. The same shell will work fine later. BTW new Federal dove loads used today. **(added later) This will only occur with ammunition, cycling w/o shells no jam, jam seems to begin with loading, and will be stuck before round is fully chambered. Once barrel is removed the slide will move and eject the shell through the port, needless to say it is unnerving to remove a barrel from a shot gun with a chambered live round.

November 26, 2007, 11:16 AM
Is this a new shotgun? My Maverick 88 was a bit 'rough' when I first got it, but that 'work polishing' of about 300 shells smoothed it right up...and smoothed up the 'operator', too. :D:evil::D:evil::D

November 26, 2007, 01:13 PM
Is there any binding at all in the action when you just cycle it multiple times without any shells in the system?

November 26, 2007, 02:24 PM
As I understand the problem, you are saying that the brand new factory loaded round gets "jammed" while going into the chamber. If the round will fully enter the chamber, then you should be able to fire it and extract it.

If the round will not fully enter the chamber, then something appears to be wrong with either the chamber or the ammunition. Either the chamber is too small or the ammo is too large (fat).

If this problem only occurs on some shells and not on others, then I suspect the problem is with the ammo. Try some better ammo.

November 26, 2007, 05:09 PM
:confused:how to take apart and reassemble the Mossberg 500--

November 26, 2007, 07:47 PM
Alright, new symptom with only one occurrence: I laid it down last night with the slide closed on an empty chamber and no shells in the mag tube. Oldnamvet, tonight I tried to cycle the action for your test. I discovered the slide release button (tab?) was in the pressed position. The action was locked tighter than Dick's Hat Band, once again barrel removal cleared the jam. I have cycled the action a few dozen times tonight with no adverse effect
1: This gun has been returned to Mossberg for these issues with no resolution.
2: This is an early to mid 80's 20ga 500C single slide bar gun in pristine condition, S/N J6300XX.
3: Probably has not had 40 shells fired due to this issue.
Once again this is NOT ammunition related OR cleanliness related, this is timing/function/action/barrel related. New Winchester/Federal/Remington loads (or now no loads at ALL), same thing.

November 26, 2007, 08:03 PM
It's still unclear to me what the gun will do or won't do. Without any shells at all in the gun, will the gun cycle and dryfire correctly EVERY TIME? If not, then it's not a problem with the shells. It's some kind of internal problem.

I'm beginning to suspect that something is wrong with the trigger assembly or some part thereof, but until I can get some clear answers on EXACTLY what the gun does or doesn't do and WHEN it does it when attempting to cycle and dryfire it, then I can't pinpoint the source of the problem.

You might try taking the trigger assembly out of another Model 500 and put it in your gun and see if that cures the problem. If it does, then you know the problem is in the trigger assembly.

November 26, 2007, 10:12 PM
Ok , Once again, The gun's action Jams upon Chambering. Will not fire because the bolt isn't in battery, action will not move. Apparently with or with out a round. I do not/will not dry fire my weapons, I have no dummy load to dry fire with. You cannot fire the weapon may be the only thing that was left out of previous posts.

November 26, 2007, 10:16 PM
Take it to a gunsmith.

November 27, 2007, 09:34 AM
You CAN dry fire a 500 without snap caps with no damage.

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