930 JM Pro - choke & jam fest

[Dixie3gun]

Hi everyone.
Have had and used mossy 500’s, Remmy 870’s, and SxS guns for 45 years.


Bought the hype and SPECIAL ORDERED a 9+1 930 JM for a 3 gun toy a week ago.
Have put 100 or so rounds through it.
Spent all day on 4th playing and fighting with it.

It chokes on 2 3/4 low “brass” birdshot. (brass meaning crappy aluminum)

Older “camo” Federal 7 1/2 dove loads jammed up “sometimes”.
(About 1:8)

Winchester UNIVERSAL 1200fps 7 1/2 shot game & target jammed up about 1:5 times.

Winchester “super target” shells are about every third or fourth shot.
So I read here a bit and swapped from those aluminum POS shells and tried a mix of everything I have on hand.

The full power buckshot and slugs fed and ejected well.
As did hi-power tall brass shells and PMC “heavy dove load” with low brass base.

Also.....
I inspected some ejected but not fired rounds and found where “something” is gouging down the side of the shells.
Plastic AND brass.




This is ridiculous for a “Ready out of the box 3gun shotgun”

Who shoots full power loads in a competition gun ???
NOBODY !!!! That’s who.
Everyone I ever shoot with uses inexpensive ammo.

So what is my options ???
Spend another $200 on aftermarket parts ???

Thinking I shoulda just bought a higher priced/quality gun from the outset.

Ordered OR3gun parts tonight.
(There goes the savings for cheaper gun)

Picking up some fresh polishing rouge monday, and will do the chamber like we do on our SASS shotguns.

Mag spring and such is good or it wouldn’t feed from tube, but will tear down and inspect thoroughly.

 

[John A.]

In fairness, many semi auto's choke on low powered shells. Due mostly to the higher power action spring. If you can find a lighter spring, that will likely resolve the feeding issues.

I would suspect that Mossberg would rather install a heavier spring so folks don't throw in magnum high brass and batter up the bolt and receiver into powder.

@MikeD may be able to help with regards to the springs or perhaps whatever may be scratching the hull. Maybe the front of the elevator or whatever the 930 calls that part. It's well known to bite thumbs. I imagine that it would do the same with shells.

 

[mikehill85]

Yeah. I have one and had major issues with it out of the box. Shells kept jamming under the chamber and not feeding in. I ended up contacting Mossberg about it. They thought it was the lifter and sent me a new lifter. I put hundreds of rounds through it trying to fix it and tried too many different fixes to mention here. Eventually I just sent it in to them for repair. They ended up replacing the receiver which they say was "out of spec". It has been running well since then (i.e. will cycle anything).

Recently, however, I noticed some issues with the bolt lock. It hasn't caused any malfunctions but the spot where the bolt lock interfaces with the bolt carrier has a big ass dent on it. I think there are issues with heat treatment or materials selection on this part. I even found a video online of someone who had the head of the bolt lock shear off leaving him with a straight blowback shotgun (yeah...not ideal). Mossberg told me my wear was "normal" but are sending me a new bolt anyway (for free). Personally, I don't buy that since none of the other parts show similar wear and this is a crucial component to the safe operation of the gun.

In my own experience, this gun is a poorly constructed piece of junk and I really regret buying it. If I could go back, I would just insist on a refund from the store that sold it to me. I recommend you do the same if you can. You've got to think that for the cost of your time, sanity, hundreds of full power rounds, upgrade parts, ect. you could have gotten a Benelli and called it a day with a gun which you know will last a lifetime.



In your case, (assuming you want to go down the perilous road of keeping the gun and trying to get it to work) since you have those strange marks on the shells, I would recommend checking the entrance to the mag tube and the inside of mag tube itself for burrs, debris, ect. If the shells are getting delayed by some sharp surface creating friction that could certainly lead to feeding problems. In that case, the shells can't get out of the mag tube fast enough to get picked up by the lifter. They actually just Loctite the mag tube in place (Assembly using Loctite...now that's quality!) so make sure it isn't loose. I actually undid it once by accident when cleaning. If you haven't already, take the thing apart (there is a good video by Jerry on Youtube on disassembly/cleaning) and remove the stupid red preservative they dose it in before shipping and check for anything out of the ordinary (sharp surfaces, obviously broken parts, ect.) especially in the mag tube/mag tube entrance. Also, tell Mossberg about the problem (if you intend to keep it). In my experience their only saving grace has been their fast response to my e-mail inquiries. Good luck! Let me know how it goes.

That said, I personally recommend just demanding a refund. I wish I had. Just my own advice. They've replaced the lifter, receiver and bolt already. I only need to replace a few parts to have an entire new gun!