Mossberg 930 Failure to Fire

[bratch]

A couple weeks ago I took apart my Mossberg 930SPX for a good cleaning after firing several hundred rounds through it with out one.

I took it to the range last night and was experiencing failure to fires. If I loaded a shell by using the bolt release button all I heard was a "click" if I hand cycled a round from the tube after the "click" it would fire. There were no marks from a light primer strike on any of the unfired shells I examined.

Any ideas as to what could be wrong? I'm assuming I boogered up reassembly but I'm not sure where or how.

 

[ArmedBear]

Wait...

If you cycled from the tube, it would fire. Would it eject that hull, pick up a fresh round and fire again without intervention?

 

[bratch]

It would fire but was not cycling.

I need to make sure I have the piston in there correctly but I am about 95% sure I do.

 

[ArmedBear]

Ah. Yeah, sounds like the piston is in backwards or something.

Don't have a 930, but have had the same problem with the bolt not closing completely when released, with everything from an 1100 to an AR-15. That's usually fouling and/or no lube.

But if it's not cycling, your gas system components are probably in wrong. I'd take it apart and follow the instructions carefully (sometimes that's hard to do, and/or the writers didn't write in a way that makes sense to me).

I had that problem with the 1100, too. The Beretta pistons are so simple, they just go one way, or they don't go together at all.

 

[bratch]

Ah. Yeah, sounds like the piston is in backwards or something.

This would be my initial thought as well but the piston only goes in one way. I had a previous piston issue with this gun so I was watching it closely which is why I don't think I put it in wrong.

I'll strip it down again and double check everything.

 

[ArmedBear]

Does your gun have a seal ring?

If so, it looks like it can be reversed. That would probably keep it from cycling, if it's anything like the 1100 I used to have.

(Page 12 of the Mossberg 930 owner's manual)

 

[bratch]

No seal ring.

 

[ArmedBear]

Hmmm...

It sure does look like a very simple gas system. How does it compensate for hotter loads?

 

[bratch]

Kicks harder

Gas system is extremely straight forward and basic. I'm thinking I messed up somwhere in the bolt assembly but I'm not sure how.

 

[ArmedBear]

You've had good luck with it otherwise, though?

I've thought about getting one for waterfowl. If they'd make it in 20, I'd already have bought one for chukar.

 

[Dirtpile]

It sure does look like a very simple gas system. How does it compensate for hotter loads?

It has vents in the forend to expel the excess gas.

You're probably right in thinking it's a bolt issue. Besides a damaged firing pin about the only thing that'll cause a failure to strike when that hammer falls is the bolt being out of battery.

 

[bratch]

You've had good luck with it otherwise, though?

Mine is the SPX which is the 18" with ghost rings.

I've had good luck once I figured out what it likes. I tried to run some cheap Winchester Super X through it and it choked about 1 out of 5 times. I replaced the Winchester with Federal Game Loads and Winchester Super Speed loads and did not have any problems. It hasn't bobbled with slugs or buck shot. I used it in a Givens Defensive Shotgun class running just over 200 rounds through it in a day without a single hiccup.

I've considered getting one of the field versions to use and keep my manual of arms consistent.

I have been extremely happy with it and wouldn't hesitate to get another.

 

[ArmedBear]

I would imagine that an 18" barrel with the same gas system as a 28" would be a little more fickle.

It's the only semiauto I know of, with a tang safety. I have shotguns with all three common safety controls, and the tang safety is the only one worth a hill of crap. The others can be so frustrating that people don't use them when they should, or they are in the opposite position from what you thought.

 

[rcmodel]

I have just the opposite view on tang safety's.

I was born & raised with trigger-guard mounted safety's, and for me a tang safety is an unnatural beast that forces me to let go of a firm grasp on the stocks grip with my thumb to use it.

I also am forced to keep my finger out of the trigger-guard, and off the trigger, if I have to use it to push a button safety.

I have seen ND's when hunting with folks who had their gloved finger on the trigger when they released a tang safety.

I am of the firm opinion they are not as safe or as fast as a push-through safety.

rc

 

[ArmedBear]

for me a tang safety is an unnatural beast that forces me to let go of a firm grasp on the stocks grip with my thumb to use it.

I've never hit anything when I had a death grip on a gun. I don't have to loosen my grip on the gun to flick the safety off, so I must be holding it differently.

I have seen ND's when hunting with folks who had their gloved finger on the trigger when they released a tang safety.

I'm sure you have. But that's a pretty stupid thing to do, walking around with your finger inside the trigger guard. I don't do that, and I don't need to be forced not to do it.

I'm talking about a gun that I'm carrying, which means with my finger off the trigger and safety on. When I mount it, I flick the safety off subconsciously, and before I ever put my finger near the trigger.

Fastest way, other than not having the safety on at all, in my experience. Also in my experience, guys with crossbolt safeties either flick them off sooner, or leave them off altogether, in fast hunting situations. That's not safer.

I can also visually check a tang safety easily. In many hunting situations, I'm flicking the thing off and on again. With a crossbolt, it's easy to lose track.

For a lot of hunting I've done, I don't have time to mess with pump guns, inconvenient safeties, etc. I like O/Us, actually. For other kinds of hunting, anything will do.

 

[Virgil47]

I too prefer a tang safety but that may be because I shoot left handed. Also if I'm not mistaken there is a "seal" ring located forward of the gas piston that can be installed backwards.

 

[bratch]

Tore it down and reassembled everything last night. I put some white out on the primers of my snap caps and it appears to be hitting the primers. I'll be taking it to the range today to see if it is fixed.

Also if I'm not mistaken there is a "seal" ring located forward of the gas piston that can be installed backwards.

The 930SPX does not have a gas ring. Some of the other models do but I'm not sure which ones.

 

[Virgil47]

Well I'm surprised that the 930SPX doesn't have the seal ring as my 930 waterfowler does. Oh well I'd hoped I could help out. Sorry.

 

[bratch]

I'm not sure why it doesn't have one but the manual states not all models do so I'm guessing the SPX is one that doesn't.

It ran great yesterday so I must have put it together wrong the first time. I put the trigger assembly in before the bolt assembly and may not have got the link arm lined up correctly.

 

[Virgil47]

Hey that's great. I'm glad to hear all is well with your Mossy.