My Mossberg 500 will occasionally fail to fire when I press the trigger. There will be a round in the chamber, but it will feel like the safety is on. I will immediately check the safety, thinking I have forgotten to place it in the fire position (which I certainly have done on occasion), but it will be off and ready to go.

 

I have not actually checked the shell, but the guys pulling for me have looked, and said it looked like a light strike. It happens pretty infrequently, but yesterday I had it occur twice in 25 rounds. It's only a minor inconvenience when shooting clays, but I would sure hate to have it happen when I'm facing an armed assailant.

 

Any thoughts on what to check?

How old is the mossberg? What brand ammo? Try another brand primers may just be really hard

Have you cleaned it recently? 

Not on a Mossberg, but on my one Winchesters and one of my O/Us, this happens if the firing pin, and firing pin hole in the bolt or breach is not cleaned and lubed on a regular basis. They seem to get a layer of crud build up in this area and causes the same FTF problems at times. A good cleaning and lube and all is well again. Usually after 250 plus rounds.

Have you cleaned it recently?

 

Wait, I'm supposed to clean it?

 

Seriously though, are you suggesting I might have disturbed something when I cleaned it, or just that it might need to be cleaned (which could be the case).

 

Smoke Eater, it's just a couple of years old, but I probably have over a thousand rounds through it. (And yes, I have cleaned it occasionally.)

Could be weak hammer spring

 

Sent from my SCH-I535 using Tapatalk 4

 

 

Seriously though, are you suggesting I might have disturbed something when I cleaned it, or just that it might need to be cleaned (which could be the case).

 

 

Both. 

If it's not going "click" the safety may be hanging up.  If it is releasing the hammer but not forcefully enough check for dirt then spring.  Ed.

Pull the gun completely apart and look for wear or carbon build up. I know its a bitc4 to do... but remove the firing pin and clean the channel. Can you eject after it doesnt fire or is it also hanging up? If thats the case ypur lifter maynot be lifting/aligning the shell right. I had a simular isue on a 870. Replaced the lifter and never had an issue again(loading that is)

My bet's on the spring!

If your saying probably over 1000 rounds you shouldn't have issues with worn parts. If you said 5,000 maybe. Sounds like it needs a good scrubbing. It's amazing how much junk works its way into some parts. Total strip, clean and lube sounds in order.

Lite hits on the primer may mean that the receiver isn't fully into battery from a short stroke, which can also be caused by crud build-up.  If you can't eject the round after the click, the extractor may not have completely jumped over the rim of the shell and engaged the rim.  This will also cause the lite primer hits you wrote about.

 

As others have said, start your analysis with a CLEAN gun and you'll be able to properly diagnose the problem.  Since the gun is practically new (4 cases of ammo), it shouldn't be a worn-out hammer spring.  More than likely a crud issue that a cleaning will resolve.  Some ammo (like Rio) is dirty as hell, and should be avoided if possible.....

 

Dave

I've literally fired thousands of shells though my Winchester pump with out a single hiccup other then 1 or 3 dud rounds.

 

A 500 should be every bit as reliable, definitely have it checked out or give it through rundown yourself before you return it to HD duty.

Thank you gentlemen (ladies?) for your helpful suggestions.  I took it all apart and gave it a good cleaning.  (How did people put guns back together before You Tube?)  It did not look particularly dirty, BTW.  Put a dozen or so rounds of buckshot through it yesterday without a hitch.  

a dozen is not nearly enough to assume the problem has been corrected.

Yes, I realize that, but that was all I had time for yesterday.  I'll go up to the clay range sometime soon and blow through a couple of boxes or so to see how it does with that.  Thanks again for your help.

Put another couple of boxes through it yesterday, and it fired every time (except for once when I forgot to take the safety off).

Thanks again for everyone's help.

Not on a Mossberg, but on my one Winchesters and one of my O/Us, this happens if the firing pin, and firing pin hole in the bolt or breach is not cleaned and lubed on a regular basis. They seem to get a layer of crud build up in this area and causes the same FTF problems at times. A good cleaning and lube and all is well again. Usually after 250 plus rounds.

I've always operated under the assumption to never lube my firing pin/hole. At most use a dry lube like graphite. The only thing i have ever lubed on a shot gun is the bolt, FCG and the rack rails.