Problem with Mossberg 500...
 

Hoping you guys can direct me in which action to take here.

I recently picked up a used 12 ga. Mossberg 500. Really looks in great shape, but I was having some issues at the range, shooting skeet, yesterday. First time I've gotten to shoot it. When shooting the Winchester rounds, I had no issues. BUT all but a few times, I had issues with the Remington ammo. Pin would strike it enough to leave a small indent, but wouldn't fire. If I tried it again, nothing. Switched back to the Winchester ammo and it would fire. We then took the same Remington rounds in a friends Remington 870 and they would fire fine.

Maybe my gun is gummed up a little from not being fired for a while or maybe something needs replaced. Any recommendations?

Re: Problem with Mossberg 500...
 

Sounds like light firing pin strikes...probably why the owner sold it. Have a competent gunsmith look at it or Mossberg factory service. It may only need a new firing pin or spring to fix it...

Re: Problem with Mossberg 500...
 

Must be a difference in primer hardness. Agreed, put a new firing pin and spring in it.

Re: Problem with Mossberg 500...
 

Take it completely down and clean it well before taking it in to anyone. If the firing pin is rough on the sides you might use a little emery cloth very judiciously.

Edit: Only do this if you are mechanically competent enough to do the job right. Probably should use a large plastic bag for taking the bolt apart so that you don't lose any springs.
http://www.urban-armory.com/diagrams/mossberg.htm

Re: Problem with Mossberg 500...
 

Ain't the only problem with those things. You can easily break the plastic top safety if it freezes up in cold weather.

Re: Problem with Mossberg 500...
 

I used to have a 500 Short Barrel, with pistol grip and Butt stock, so I could switch back and fourth... Never had a problem feeding this thing any kind of ammo from premium, down to the Aldi's generic six dot box that just says ""Bullets", it would shoot everything no probs...

Let us know what your fix is, just incase someone we know, happens to have this same issue...

Hope it works out for ya...

Re: Problem with Mossberg 500...
 

Sometimes a bit of shaveings get behind where the fireing pin protrudes through the hole stopping the pin from its full motion. (Not Specific to Mossbergs)

I've seen it on striker fired pistols. Cleaning out around the fireing pine allows the full range of motion on Glocks and others----Maybe the same type of thing.

Spray with Brake cleaner to wash out---Maybe

Good Luck

E-A

Re: Problem with Mossberg 500...
 

The proper procedure for fixing any of the mossberg's problems is to throw it in a creek and buy the 870 you should have bought in the first place.:aetsch:

Have I mentioned how much I hate jambergs?:favorites21:

Re: Problem with Mossberg 500...
 

^ hah. Oh well, live and learn.

Thanks for the help...most of you. I'll keep you updated on what the problem was.

Re: Problem with Mossberg 500...
 

Everyone has their favorite and worst of everything, shoe, trucks, strippers, guns, Sub woofers, Ammo, etc...

I've got well lets say a couple Mossbergs, a couple Remingtons and a few Brownings and I don't know how many models of each of those I've shot...

Back to the point, I've never had a problem with my Mossbergs or any of the above mentioned for that matter... They simpley work and work well...

The only shotgun I've seen malfunction was some off branded one my dad picked up for like 70 bucks at a feed store..

Re: Problem with Mossberg 500...
 

A brief update: I ended up disassembling mossberg and cleaning it up. It was pretty damn grimey and after cleaning it, and putting it back together, it seemed to function a lot smoother.

I used this instructional video to disassemble and reassemble the gun for anyone's reference:
I haven't got a chance to fire it yet to see if it was as simple as a good cleaning/lube. I'm thinking it won't be that easy and that the spring and firing pin will need replaced. We'll see. I'll update this thread once I get a chance to shoot it.

Re: Problem with Mossberg 500...
 

you might look at the fired hulls and compare with different brands or friends hulls to see how deep the primer dent is...

Re: Problem with Mossberg 500...
 

If its got an engine, firing pin, or boobs you are going to have trouble with it at some point!

Re: Problem with Mossberg 500...
 

I've got a Remington 870 and a Mossberg Maverick 88, both 12ga pumps, and I like them both, but prefer the Remington. This is one of 2 problems perhaps, IMO:

• The gun has set up in the cocked position for years and the hammer spring has taken a set and gone weak.
  
• The inertial firing pin area was gunked up or otherwise obstructed (inside the bolt, and I see it there in the vid from underneath)

I'd clean that firing pin area and related holes very well, maybe soak the entire bolt and trigger assembly in kerosene (an old cleaning trick of mine to float and loosen crud and sludge)...... Then use toothpicks and pipecleaners to pick and scrape gunk or residue as you push it against the detent spring with a 1/8" dowel or equivalent to check a free-floating inertial glide forward into the primers.

It's a well known fact that various brands of primers exhibit different hardness and variances in energy impulse needed to ignite them. Right now I have a problem with an vintage 1984 Beretta model 21 Bobcat .22LR pistol. It fires any CCI brand .22 just fine 100%, but on Federal or Remington brand ammo, it fires only about 2 out of 3. I can barely see the dents on any of them in any case, but it's obvious I prefer the CCIs now for reliability alone because they're so soft to fire.

I took out the pistol's little inertial firing pin with a punch and made SURE it works slick as owl feces after my kerosene soaking and scrubbing with a toothbrush. It helped some, but very little, so now I'm replacing the hammer spring and confident that the age on it is the major culprit in my case.

If the floating firing pin on your Mossberg moves smoothly and very freely when pushed against the detent spring which keeps it away from the primers until it is launched forward by the hammer, and that does not fix it, then I'd replace the hammer spring down in the trigger assembly. This procedure may require some gunsmith expertise.

And in my opinion NEVER use WD-40 on any gun part, as it will over time turn to a sort of varnish that can cause all sorts of problems like gunk in the firing pin hole. Kerosene tends to flush it all out... I hope you enjoy your functional Mossberg 500 after the fix, have fun fixing it for the experience, and good luck!

Re: Problem with Mossberg 500...
 

I'm thinking that the person who had it before had the same issues with this firearm. With shotguns you don't think of headspace. My first thought was that very thing, that or firing pin wear. Since it is used, how much was it used? Did you mic the rims of the two brands of shells. Just a slight difference would make all the difference in rather the firing pin struck the primer hard enough to fire it or not, if the guns headspace was excessive. While the issue very well could be a really dirty bolt and firing pin, don't rule out the possibility of excessive headspace.

Re: Problem with Mossberg 500...
 

There are major differences in hardness between primer brands but your gun should shoot any of them. If cleaning it didn't work, it is almost certainly the spring. I don't know how your action works but if there is a hammer involved, the trigger mech will have to be taken down. Unless you are very competent, that is a gunsmith job. As a more remote possibility, the firing pin could be too short or too large in diameter.

Re: Problem with Mossberg 500...
 

Thank you guys for the insight. After taking it apart, cleaning it and lubing, and finally being about to get to the range, I'm still having the problem. I guess it sounds like I need to take it to a gun smith. Would you suggest taking the entire gun, explaining the problem and dropping off for repair? Or just taking the firing assembly in and letting them know I need the spring and firing pin replaced? Also, what could I expect to pay for something like this? I'm just bummed it sounds like I can't fix it myself.

Re: Problem with Mossberg 500...
 

Yeah, find out what the tariff is going to be to get it fixed. I'm sure you're going to pay for an hour of the gunsmith's time anyway. I personally wouldn't buy a used gun of that sort. When you can get a real good pump gun for $300.00 new, it ain't really worth it. I've bought some used handguns, and rifles, but all of my shotguns were purchased new. Good luck, hope it's an easy, cheap fix!

Re: Problem with Mossberg 500...
 

Take a chance - it might be cheaper than you would think. I disassembled my Grandpa's Colt Woodsman a little too far after inheriting it, and after a couple of attempts and several hours over the course of a few months, I finally called a guy whose card I'd had lying around. He inspected it, cleaned it up, put it back together, and wouldn't even charge me for it. Said it took him less than 10 minutes.

In short, jobs that might seem hard for us regular folks might be a snap for guys with the training and tools. Good luck!

Re: Problem with Mossberg 500...
 

First and foremost, it probably IS the firing pin spring.

But the firing pin itself could be broken and unless you pull it from the bolt, you will never know.

Take a look at this exploded diagram on Numrich Gun Parts for the Mossberg 500. http://www.e-gunparts.com/productsch...Model=0840z500

There are FOUR parts involved. The firing pin, the firing pin washer, the firing pin spring and the firing pin retaining pin.

To remove the firing pin, you will have to remove the retaining pin, which means you need a pin punch and a light weight hammer (mine is a 4 oz ball peen hammer). After the retaining pin is removed, the firing pin, washer and spring should literally fall out the rear of the bolt (though a fair warning is given here - if the firing pin is under a lot of spring tension, it CAN shoot across the room - been there, done that).

At this point you will have a pretty good idea what the problem is. The firing pin itself might be broken or just worn (making it shorter than it should be). Same for the washer and the firing pin spring.

If purchased from Numrich, the firing pin itself will be $16, the firing pin washer is $3 and the firing pin spring is $5, so your parts total is going to be about $24, plus s&h, which will probably run about $6, depending on where you live and how quickly you want these parts delivered. If I were doing this job, I would suggest a new retaining pin as well for an additional $3, which would bring the total up to $33.

A gunsmith will probably charge you between $30 - $50 for disassemly/lube and reassembly plus the parts costs. He might charge you a little more for the parts, because he wants to make a few bucks there.

Over all, you should be able to take the whole gun in, get the bolt checked and the firing pin/washer/spring replaced for under $100, again depending on where you live. Take in some Remington shells that were NOT firing properly so he can test fire it for you before you get it back. This should resolve this issue.

Or you can do it yourself, as this one is pretty simplistic as gunsmithing jobs go.

Re: Problem with Mossberg 500...
 

Fix it yourself. This is how you learn. If you do not have the tools....get them....You can get a pretty good set of hardened precision punches at Harbor Freight for under $10. And a complete set light weight ball peen hammers for another $10.

When working on guns, you may need a bench block to work on things when driving out pins, etc......just use a block of wood....drill holes in it for clearance if needed. Spread out a large towel on the kitchen table when working on these things.....it catches the little springs and pins you will drop.

I've had broken firing pins in the past....I've even made 2 from scratch ou of old pieces of die ejector/core pins or drill bit shanks.....man are they hard, you can cut them with a file...takes some time, but you can make them from scratch.

Remember - most of your free time is ....FREE!!!! Learn something and build these skills.

I do most of my precision repair work at the kitchen table....has a bright light.....overhauled many a carb in the kitchen.

On a side note.....you would be amazed what you can do with a file......just this weekend, I fixed up a crappy little 2 HP Briggs & Stratton engine I got for just about nothing. After getting it running...... it had a 5/8" crankshaft ....and I needed it be 1/2"......so I screwed it down to a board, fired it up and cut the shaft down under it's own power....using a file and my hands......I was amazed that i was able to cut it to within 0.0005 - 0.001 inch diameter ...worked perfectly...cost nothing. Amazed how well it turned out. As good as a chucking the crank in a lathe....plus i did not have to completely tear the engine down to get the crank out....

This is how you learn!

Re: Problem with Mossberg 500...
 

You guys have me convinced. I'm mechanically astute when it comes to cars and what not, so I'm sure I can handle this. Guns are just new to me, but I'm sure I can figure it out. Now I know what tools I need, where to get them, and how to go about it. Thanks for the help and I'll report back later on my progress.

Re: Problem with Mossberg 500...
 

Look through Midway's site for the parts related to your problem.
If you dream it you can do it!
http://www.midwayusa.com/browse/Brow...021***11557***

Re: Problem with Mossberg 500...
 

Well just put in my order for parts. No turning back now... :D

Re: Problem with Mossberg 500...
 

Well done, that's the spirit! I you can handle cars, guns are a no brainer.

Re: Problem with Mossberg 500...
 

A couple of 'cheats'.

First off, the gunsmiths supply company is called 'Brownells'.

You can get a lot of good tools from them. While they are not cheap, these are generally specific tools for specific jobs.

Secondly, I use HOCKEY PUCKS with holes drilled in them to drive pins out of firearms. Smaller parts can fit on just one. For putting longer guns on them, two or three hockey pucks under the work helps immensely. I even milled a 'V' down the middle, so I could steady rifle barrels in them. They are called 'Bench Blocks'. Brownells sells theirs in the $20 to $40 range.

I made mine for about $5 each. I have four. But that's just me. I also cut one hockey puck up and use the pieces as softer sanding blocks. They work great as well.

Good luck and let us know how it turns out. It IS an easy job. I've always called springs 'air soluable parts', because as soon as they come out of the gun, the seem to disappear.

Re: Problem with Mossberg 500...
 

Well got the gun all rebuilt and cleaned up this weekend. I have to say after getting a cheap set of punches at Sears ($10), already had a small hammer, and just found a 2x4 wood block and did a little drilling...it went pretty smooth (after I realized where the retaining pin was...holding the firing pin in. haha).

Anyway, the old spring looked the same as the new one, but I replaced it anyway. The washer that was sent had a smaller diameter and didn't fit, so I used the old one. Not a big deal as it looked fine and I'm not going to hassle with sending it back over a $3 washer. The firing pin, on the other hand, I believe may have been warped. Besides having a dull front end, it also did not slide freely in the bolt and would get hung up. The new pin slides easily and has a good point.

I was planning on going shooting on Sunday, but a snow storm nixed that idea. Hopefully this solved the problem. Anyway, I have to say that anyone can really do this if you take your time, and look at a schematic. I'm glad to have learned how to take this thing apart. :D

Re: Problem with Mossberg 500...
 

Another very handy tool is a large dry-cleaner's bag (the type they put over clothing when it's returned to you). VERY handy in catching springs that fly loose, never to be seen again. Do your disassembly/reassembly inside the bag.

Re: Problem with Mossberg 500...
 

Cool, the best part is you were able to positively identify the problem. Also the shotgun isn't a mystery any more.

s

Re: Problem with Mossberg 500...
 

Well, I took the gun to the range a couple weeks ago, but forgot to updated this. Still having the same damn problem. So here's a recap for anyone just joining us...

Having occasional no-fire on my Mossberg 500: Winchester ammo fires every time, no problem. Remington ammo fires 1 out of every few, leaves indent on back of cartridge but doesn't fire. Have replaced the firing pin and spring, and cleaned up thoroughly.

After the range, went over to a friends that has the same model. We stripped down each and compared to see if there was any obvious differences...none were spotted. We decided next time we go to the range, we'll try swapping out the trigger assembly to see if that has any affect.

Any other advice before this thing becomes a permanent closet fixture?

Re: Problem with Mossberg 500...
 

Only shoot Winchester...or trade it for a Remington 870. I personally would never own a "summer-time" gun ("summer-time" it works and "summer-time" it don't). Get rid of it.

Re: Problem with Mossberg 500...
 

I'd rather not own a summer time gun either, but I'm hoping that I can figure out what the heck is going on. I don't want to pass off the problems to someone else, so it's either take a large hit on selling a 'parts' gun, or hopefully fix it. I guess until then, I'll see if I may be able to trade or sell my remaining Remington rounds.

Re: Problem with Mossberg 500...
 

At this point, I'd take it to a competent gunsmith. You'd probably be investing another $50 in the shotgun. Did you buy this shotgun new or used? Warranty?

Re: Problem with Mossberg 500...
 

Just for the heck of it, try switching the barrel too (headspace?).

Re: Problem with Mossberg 500...
 

Ag_man, I bought it used...obviously a mistake I won't make in the future.

Quixote, I've tried both of my barrels, doesn't seem to make a difference.

One thing I do recall though, is that if you would cock it with force, it would seem to fire the Remington. The Winchester didn't matter as it would fire every time. It seemed though, if I cocked it hard, it had a better chance of firing. Make sense to anyone?

Re: Problem with Mossberg 500...
 

It sounds like the firing pin still, even after the replacment. Maybe the remington shells have a deeper seated primer, so if your firing pin isnt striking deep enough anyways, then the deeper seated primer might just be out of reach. Going to a gunsmith would defently be advised.


If the repair goes to no avail, and you dont want to invest the time or frns let me know. Im in need of an 18.5 inch barrel ;)

Re: Problem with Mossberg 500...
 

K+ thats the kind of thinking I like, clever, a time saver and the motor is still intact.

I've got a pile of bits left over from disassembling and reassembling all sort of things. Not guns mind.. nothing that serious, cars, toasters, that kind of thing. Always seem to have a couple bits left over.

To be honest I stopped pulling things apart because of this.....

Re: Problem with Mossberg 500...
 

I said in post #15 "HEADSPACE". However the bolt locks into place is also a function to consider in headspace. When you ram or "cock" it hard you shove the bolt home tight, tightening up the headspace. It might be just a slight difference between the brand of shells in size that you have the fire/no-fire issue. Head space is figured by the rim in a shotgun, replacing the firing pin does nothing to improve head space. Think bolt, receiver, or barrel. You've tried different barrels so that leaves the other two options. don't waste your money on a different trigger assembly. Either pay to have a gunsmith look into it or.......!

What I'm thinking is, either a worn bolt or a receiver worn to much to lock right. the bolt can be replaced or you can sell it as a parts gun if it's your receiver, a new bolt might tighten it up enough for a little more use, few thousand rounds, but I doubt it, sell it as is or for parts, redeem what you can from it. Buy the Remington 870 and "forgetaboutit"!

Edited to add: We don't need no summer-time guns!

Re: Problem with Mossberg 500...
 

TRUTH! More of us need to learn to do these things ourselves.