Mossberg 835

[MtnCreek]

I need advice on repairing a Mossberg 835 please. I have an old 835 that was purchased new in the mid 90’s, somewhere about the time they came out. The last few years, it has sat unfired because the action will open when fired. (yea, add a spring & I’ll have a semi-auto… ) Comparing it to a newer 835, the trigger group assembly seems to fit loose on the old shotgun. The trigger group is made from plastic or similar material. I assume this plastic is worn somewhere from recoil during firing, probably in the pin holes. The pin holes in the receiver seem to be round / tight, so I’m pretty sure it’s not the issue. I can purchase a new trigger group assembly for ~$40, but before I started buying parts I wanted to see if anyone here has had similar experiences or can confirm that I’m on the right track.

Thanks!

 

[amflyer]

Are you sure it's not just the inertial force of the recoil acting on the slide moving the now-unlocked bolt?

 

[MtnCreek]

It is. The issue is that it does not stay locked. For years, it would stay locked until the forearm was moved slightly forward, then the action could be opened (pumped). Now it will open (pump) when fired. The trigger assembly no longer fits securly; the front of the assembly moves down when pressure is applied to the forearm with a locked action. The release to unlock the action is located in the trigger assembly, so there is some relation there, I'm just not sure how.

 

[rcmodel]

For years, it would stay locked until the forearm was moved slightly forward, then the action could be opened (pumped). Now it will open (pump) when fired.

Sounds to me like it finally got broken in and is now working right.

You should not have had to manually push the forearm foreword to "unlock" it after it was fired so you could pump it.
(Unless it was dry fired and there was no recoil to release it.)

Recoil from firing is supposed to release the action lock on any pump shotgun so it can be pumped.

In other words, the forearm assembly stays where it was due to inertia, while the rest of the gun recoils.
That right there is what should unlock the action lock.

Not having to manually push it foreword by hand every time you shoot.

rc

 

[MtnCreek]

I’m doing a poor job of communicating, sorry. When fired, the action opens and the forearm slams all the way rearward. I’d say the hull is out of the gun before the shot leaves the barrel (hull has less distance to travel).

I have multiple Mossberg pumps (500’s, 590, 835), Remington 870’s, BPS’s and on old Dept Store pump that don’t do this.

 

[rcmodel]

Oh!

Well there is this:
http://www.brownells.com/.aspx/pid=...ossberg__835/Product/TRIGGER-HOUSING-ASSEMBLY

rc

 

[Kp321]

Several years ago, I had several Mossberg 500's come in with the plastic tabs on the front of the tg broken. Apparently they had a bad batch of plastic or some solvent was attacking it. I was able to fix them by cutting a slot across the front of the tg and epoxying a piece of steel, 1/8" thick, in place to replace the plastic tabs.

 

[RaceM]

On a Mossberg the slide release bar is driven by the hammer. When in the fired position (down) the hammer pushes a spring that pushes the slide release bar, allowing the action to open. The reason you had to move the slide forward after firing was to take bolt pressure off the release bar nose so it could drop.

Sounds like your slide release bar is in the released position. If it is you'll get the condition you have. Could be a broken spring for the slide release bar or a missing pin in the base of the hammer for that spring. Also check that the locking lug on top of the bolt and the locking recess in the barrel extension aren't rounded off.

 

[MtnCreek]

Thanks for the info! I'll go through it this weekend before ordering parts.

 

[earlthegoat2]

On a Mossberg the slide release bar is driven by the hammer. When in the fired position (down) the hammer pushes a spring that pushes the slide release bar, allowing the action to open. The reason you had to move the slide forward after firing was to take bolt pressure off the release bar nose so it could drop.

Yes this is also similar to how the 870 works as well. It has nothing to do with inertial forces of recoil and everything to do with the mechanics of the trigger group. So when the gun is fired, in theory at least, at the point of ignition, the slide unlocks. At that point inertial forces can act on the slide and cause the condition you are describing also. If you were to dry fire it you should also be able to work the slide between firings. There were issues in the past with these guns locking the slides forward but not disengaging the disconnector which would make it so the slide was locked where it was supposed to be but the gun was unable to fire.

Tell me, what kind of loads are you shooting. That is a 3.5" chamber gun and if you are shooting some hot ones that slide could very well come all the way back under the harsh recoil of of those magnum rounds. If you are shooting lighter loads it could still happen. Sometimes if you do not have the stock tight to your shoulder it gives the gun a "running start" to work the slide backward under recoil inertia.

Without the gun in my hands the condition you describe sounds normal.

 

[guns54]

Mossberg-835

Hes right about it just got broke in. Mine was the same way. Nothing wrong with it.