Mossberg 500 problem

Discussion in 'Technical Questions & Information' started by Roadkil, Jan 5, 2010.

  1. Roadkil

    Roadkil New Member

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    I purchased a Mossberg 500 combo shotgun brand new back 1996 with a fully rifled slug barrel. I used it as a combo for the first few years and decided to make it a dedicated slug gun for deer only in 2001. I had to put a scope on it since the iron sights were so far off that the best I could get it in was to hold 8 inches below my intended target and sometimes that was just too much to remember when shooting at a deer. Once the scope was on, and after shooting several brands of ammo to find the best grouping I ended up with a really nice slug gun for deer that has served me well until now.

    While sighting the gun in before opening day this year I had a misfire, pulled the trigger and click no bang, so I ejected that shell racked another and pulled the trigger and the gun went off. The unfired shell did have a light indentation on the primer. I fired the gun 4 more times at the range without any problems so I figured I had a bad shell. Opening day I shot a nice mature doe, without incident. Then on the extended gun weekend I had another misfire on a doe @ 20 yards, pulled the trigger and click only, no bang. By the time I ejected that shell and racked the next the deer was in the next county! The shell, a Remington Copper Sabot 2 ¾, did have a light indentation on the primer. It was cold and snowing/raining that morning, high of 32 degrees for the day; I think it was about the mid 20’s when I attempted to fire. So now I am thinking that it may not be bad shell at all and a possible maintenance issue so I went home, tore the gun down, cleaned the bolt with carb cleaner, lightly oiled it up with Hoppes and went back out the next morning.

    The next morning at daylight I pull the trigger on a doe and the gun fires. The deer ran about 30 yards and fell but kept trying to get up and run, so I went to fire another round and again there is only a click, I pull the forearm back but do not eject the shell and slam it closed pulled the trigger and the gun fires; however because the deer is now standing and facing me I rushed the shot and missed. I eject that shell and rack another pull the trigger and click. Did the same as before, pulled the forearm halfway back without ejecting that shell and slam it shut, pull the trigger and the gun fired and put the deer down.

    I had 3 shells left, two with indents on the primer and one without, so after I field dressed the deer I decided to shot each round. On each initial pull of the trigger all I got was a click, no bang. When I pulled the forearm halfway back then slammed it shut then the gun would fire. So again I took it all apart cleaned the bolt with carb cleaner and lightly oiled the firing pin and spring assembled the gun and went out to the firing range. I shot ten rounds without any problems, back home I took it apart again and cleaned it in the same fashion and placed it back on the wall.

    Well I got to thinking that each time this happened the temperature outside was below 30 degrees, so this past Saturday I went out to the range again, the high for the day was going to be 23 degrees, and did some more shooting. Well the first round went off and after that I was back to pulling the forearm halfway back, slamming the shell home and then it would fire.

    I am thinking it is either a weak spring, bad firing pin, brand of ammo, head space issue, or all four, but my question(s) is how many here have the same type gun and how many of you, if any, have experienced the above. If you have had the same experience how did you fix it? Has anyone heard of this happening before to any shotgun?

    Since I made this a dedicated slug gun the gun at most has 18 rounds or less through it a year, and as I stated above I use Remington Copper Sabot slugs in 2 ¾” length. The gun is cleaned after each use and once a year broken down for a complete cleaning. I have not attempted to fire the gun under the same conditions with another brand of ammo as of yet. I am thinking that before I do anything else that I take it to a gunsmith, but I am curious if this is a common problem or not. Thanks in advance for the help.
  2. Sandman

    Sandman New Member

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    I have a mossberg 500, never had that issue. Sounds like a problem in your firing pin mechanism (bad pin, weak spring, etc.)
  3. petesusn

    petesusn New Member

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    I also have a Mossberg 500 and have never had your problem. As Sandman said, might be the firing pin mechanism.

    Any gunsmiths out there?
  4. Helix_FR

    Helix_FR New Member

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    No this is not common to the 500 but it is a common problem to this particular type of action. My first thought on this is there is something occasionally blocking the pin path. I know that you cleaned everything out but check the pin channel in the bolt for fouling, pay close attention to the pin hole in the bolt face. Fouling can build up in there and stop the pin short. Also your slam fire condition suggests to me the the pin is also sticking in the channel. Make sure your pin spring is not binding.
    Weak spring is a possibility but usually a weak spring is more consistent along with a damaged firing pin being more consistent in misfires.
  5. Gabob

    Gabob Active Member

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    Grease on the firing pin or mechanisim will harden in cold weather and cause misfires. Did you get the carb cleaner in the firing pin channel and around the springs to degrease them?
    I once missed a feral dog chasing my calves because the grease in my revolver slowed the hammer fall
  6. Roadkil

    Roadkil New Member

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    As far as I could tell all grease was removed and a light amount of Hoppe's oil was reapplied before reassembly and operation of the gun. I have not physically removed the spring or firing pin from the bolt yet.
  7. Roadkil

    Roadkil New Member

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    I'll have another look at it and see what I can find.
  8. Jim Hauff

    Jim Hauff New Member

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    This is a "common" problem with Mossberg 500 series - you must make sure that the slide is forcefully pushed forward to fully seat the bolt and cartridge - Mossberg's will allow hammer fall if bolt is not fully "in battery" - I've had this "problem" with two Mossbergs -a 500 and a 535 (which I currently use for trap shooting) - you must remember to fully close the bolt - especially in cold weather.

    I bought my 535 back in February of '09 - I've fired almost 4000 rounds through it in that time. I've had approx. 20 instances where the cartridge failed to fire, and exhibited a "light" strike in the primer - second time around, made sure the slide went full forward with enough force and - they all fired. All the failures were with Federal Gun Club ammo, during fairly cold weather and I'm presuming I hadn't seated the bolt fully into battery. I had similar instances with a 1998 vintage 500A. Several other shooters at our club have experienced the same problem. Sounds an awful lot like what the OP experienced.
    Last edited: Jan 5, 2010
  9. Roadkil

    Roadkil New Member

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    Interesting. I also own a 535 combo that was given to me as a gift from my BIL a few years back. I use it a few times a year, mostly for small game, but have not had this issue with the 535 yet.
  10. old semperfi

    old semperfi New Member

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    i live in southern indiana,old country boy at hear
    possible mechanical problem,however i would purchase another brand of ammo and try again.if no problems then i suggest you contact ammo maker to see if any other complaints old semperfi
  11. Jim K

    Jim K New Member

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    Did you clean the locking lug seat in the top of the barrel tang? If dirt or grease gets in there, the locking lug won't seat and will block the firing pin. (This is a safety feature to prevent firing unless the bolt is fully locked, but you need to keep that hole clean.)

    Grease or crud that would be soft and compressible at moderate temperatures can become rock hard at 20 degrees.

    Jim
    Last edited: Jan 5, 2010
  12. Helix_FR

    Helix_FR New Member

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    I was just wondering if they had a pin lock on those to prevent firing w/o the bolt being locked.....
    Thanks Jim
    My strong suits are the Hi Standards and Winchesters and older Remingtons. Haven't messed with the 500 too much b/c some people don't find them worth fixen:confused:
  13. Tinman1986

    Tinman1986 New Member

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    Ive never had that problem myself, and ive shot everything from #9 shot to .690'' R.ball form 100*F to -10* in the woods coming from a hot home. Never had a misfire, always had a large dent from firing pin on primer surface.
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