Misfires with Mossberg Model 46 Mb .22

[Charlie Martinez]

After not firing my Mossberg (Mod 46 M (b)) for a few years I brought it to the range & for the first time it started misfiring a round or two, then OK for a few then misfiring again. The misfired rounds were dented at the rim but did not detonate. I tried different ammo & the same thing happened. Then I fired the misfired rounds again with another gun & they all fired. i think I established pretty well its an issue with the rifle not with the ammo.
I have a couple of questions:
1. Could the problem be caused by gumming of the spring due to long storage time. I pulled the bolt out & its clean but I have not fired this rifle for this long a period of time so I'm asking.
2. If its not likely to be a cleaning issue what would need replacement ? I assume it's either the firing pin or the spring, or both? Like I said earlier the misfired rounds were dented. Is there a way to tell?
3. If replacement of either the pin, the spring(or something else) is needed is this something I could do without special tools or will a gunsmith be necessary?
4. Does anyone know a good source for parts for old Mossbergs?
Thank you in advance for any help you can provide.

 

[243winxb]

Check gumming first. Slow velocity pin will still dent the round well.

The firing pin spring can wear the pin channel. The grooves may slow the pin. Its possible to turn the spring around to stop the drag. I did.

Headspace problem- the bolt handle rides on the action to lock the bolt. The contact area on the bolt handle can wear. Seen one. I increased firing pin travel. A quick fix, if headspace is not excessive.
With a round chambered, in a safe manor, try pushing the bolt forward. If it moves forward a lot, may need repair.

My bolt needs a gap or it may misfire. Why i dont know.

 

[Charlie Martinez]

I too suspect gumming because it never happened before and I don't think firing pin & spring wear out while sitting in a gun safe. Any suggestions as to how I can get rid of the gumming problem?

 

[243winxb]

Take bolt apart, clean with hoppes no 9 bore solvent. Dry.

Or just spray with WD40.

 

[Charlie Martinez]

Thank you very much. I'll let you know how it works out.

 

[Charlie Martinez]

I have never taken a bolt apart. It doesn't appear to be a big deal but are there any pitfalls that I need to avoid getting into?

 

[243winxb]

Dont loose a part. But an easy job.

 

[Charlie Martinez]

Unbelievable! I would have never figured out that that piece unscrews & all comes out.
PS: Probably a good idea that if I take it apart I do what he did & buy a new firing pin.
Take care & thank you very much.

 

[Scooter22]

The tail piece may be stuck on. If it is you may want to toss the whole bolt in a can of paint thinner or similar solvent and let it soak a couple days. Then wrap some leather or inner tube around it and carefully clamp in a vise and give it a twist. I've done this with a lot of old Mossbergs. Clean the FP channel out and also the sides of the FP. Also look up into the front of the bolt where the bullnose of the FP fits and make sure theres not compressed, hard gunk there. Good luck.

 

[Blue68f100]

Clean the chamber real good too. I've seen debree (lead, wax, powder) build up keeping the round from fully chambering. I have one gun that this must be done ever 2k rounds or I will start having problems.

 

[Charlie Martinez]

Sounds like a good cleaning might do the job. Hopefully.
Thanks

 

[SGW Gunsmith]

I too suspect gumming because it never happened before and I don't think firing pin & spring wear out while sitting in a gun safe. Any suggestions as to how I can get rid of the gumming problem?

Gumming doesn't happen while a rifle, or any firearm, just sits in a gun cabinet. While it is true that excess lubrication, depending on what was used, can coagulate over time, but the ammunition firing would not be sporadic, it most likely wouldn't work at all. It's normally caused by over-zealous lubrication that gets mixed with carbon from shooting and it normally doesn't affect the bolt parts.
You haven't mention which ammunition you were using. Is it one specific brand? Have you tried any other brands? Now, if you suspect that the firing pin is acting sluggishly, then you would do well to clean the bolt completely. It's amazing what a soaking over-night in kerosene will do to get parts moving as they should, followed by a blast of compressed air.
Consider this, each time a .22 round is fired, it will push most all of the alleged build up in the front of the chamber forward, and out the barrel, so think about how "stuff" could build up and still allow a bullet to move forward, or a round to even be chambered.

 

[Skylerbone]

If ever you’re in need of old Mossberg parts, these are the people to contact. Got my 80 year old up and running (and scoped). https://www.havlinsales.com