Firing problem with Mossberg 590

[dwolsten]

I'm not sure if this is the right forum, but here goes:

I have a Mossberg 590 12-gauge that works pretty well overall, except that it has a small problem with an excessive number of misfires. When I look at the cartridges that misfired, it seems that the dent made by the firing pin is not as deep as it should be.

I've disassembled the gun and the trigger group and didn't find any obvious problems, so I'm wondering if anyone knows what the usual culprit for this problem is. Is the firing pin bad? Is the mainspring too old (the shotgun hasn't been fired that many times, though it's probably about 8 years old)?

Thanks!

[DefensiveCarry.com]

[MNBurl]

Check the firing spring and pin.

[dwolsten]

They both look OK as far as I can tell. The mainspring (the one that forces the hammer up) (I assume this is the spring you're referring to) still seems to be quite stiff, and the firing pin looks fine on the outside. But without references to compare to, I'm not sure I'd be able to see a problem with either one unless it's obvious.

[razorblade]

You've had it for eight years, or you bought it from someone that's had it for eight years? If you've owned it for eight, has this been a continuing problem, or something that occured just reciently? did the rounds that didn't fire come from the same box? Have you tried with a different brand and received the same results? I don't think it's hard primers, but it is a possibility. But even if they are hard primers, the rounds should fire if you've keep the trigger group stock (read: no kitchen table gunsmith work). My guess, it's a bad hammer spring and it needs to be replaced. You get one from the manufacturer or Brownells.

[SIXTO]

I second razorblade. If it were mine, I'd just replace springs once ammo is ruled out. If I'm wrong your out a couple of dollars, but you have new springs.

[dwolsten]

You've had it for eight years, or you bought it from someone that's had it for eight years? If you've owned it for eight, has this been a continuing problem, or something that occured just reciently? did the rounds that didn't fire come from the same box? Have you tried with a different brand and received the same results? I don't think it's hard primers, but it is a possibility. But even if they are hard primers, the rounds should fire if you've keep the trigger group stock (read: no kitchen table gunsmith work). My guess, it's a bad hammer spring and it needs to be replaced. You get one from the manufacturer or Brownells.

My wife's had it for ~8 years; we recently married. I believe the problem has gotten worse over time. It's happened with all kinds of rounds, different brands and types (#00, #8, etc.).

I have taken apart the trigger group before I realized how easy it was to replace the mainspring, but I got it back together and the gun works just as well as it did before (but still with the problem obviously).

I second razorblade. If it were mine, I'd just replace springs once ammo is ruled out. If I'm wrong your out a couple of dollars, but you have new springs.

I'll try this out; it's really easy to replace the mainspring.

Thanks everyone for the advice!