Beretta 3901 problem

[sammyspizza]

So I've had my 12 ga. Beretta 3901 for about 5 years and it never had a single problem until this year. One day I took it on a duck/pheasant hunt and put a few high powered 3'' loads through it and the last few rounds of the day the bolt wouldn't come back into battery.
A few weeks later I went and shot clays with it and put only 50 rounds through it and the last couple rounds the bolt wouldn't go back into battery. And I knew it was going to happen again because as I shot more, the action would return to battery slower and slower. I know how to clean the gun really well (but i have never cleaned the recoil spring or anything inside the stock). Do I need a new recoil spring? I've never had issues with this gun before... Thanks

 

[allaroundhunter]

By cleaning the gun really well do you clean the action and bolt assembly?

 

[oneounceload]

Seems a little better cleaning is in order - most of these guns are good for several thousand rounds between cleaning - start with the ports and a good pipe cleaner

 

[Milkmaster]

I do not intend this question to be insulting. What do you mean by cleaning the gun really well? Explain your cleaning process so that we may discern the steps and identify something that you might have missed.

 

[Hopkins]

Its not difficult to remove the stock and then the recoil spring. Dirt can migrate into the spring and its housing impeding its function making going into battery sluggish or incomplete.

 

[Virginian]

"Really well" includes the action spring. If you needed a new spring it would do it all the time. Poor thing is dirty is my bet. I was going to say I can't believe you asked this, but I can. The biggest enemy of ANY semi auto is the nut on the back of the stock.

 

[Milkmaster]

Did cleaning it really well include removing the trigger group, and disassembly of the barrel, bolt, and gas system?

 

[FITASC666]

Sammyspizza,

I had the same happen to me lately. After the ''Divorce'' and moving, I kept on shooting but neglected the cleaning. Came a point where event heavy loads were not cycling properly. Took the gun apart, I mean all, stock off, trigger set...etc..The hard part to clean is the gas dispersal cylinder that cakes up with carbon. I have the luxury of a friend with an ultrasound cleaner that made it like new. I suggest you get to this part as it is critical in the whole process.

Good luck and have fun shooting!

 

[sammyspizza]

Cleaning it "really well" means I took everything completely apart and got all of the dirt and grime off of everything except for the recoil spring, and it still malfunctioned 50 rounds later with light loads. I guess I'll clean the spring and housing and if that doesn't work I'll buy a new spring

 

[sammyspizza]

Virginian... what do you mean by that? The stock was also somewhat loose feeling I noticed..could that be the problem? It was screwed on tight but still felt loose

 

[orphanedcowboy]

Virginian... what do you mean by that? The stock was also somewhat loose feeling I noticed..could that be the problem? It was screwed on tight but still felt loose

Is the shim in there? Are they correctly assembled. 55dx shim with 55dx washer?

If not it could be binding or have bent the tube.

Clean the spring housing and spring thoroughly and you should be good.

 

[sammyspizza]

The shim is in there. but when I hold the gun by the the stock, the rest of the gun almost slightly wobbles a bit. I dont know why.

 

[BigJimP]

I think the loose stock is your problem ...there must be a nut on the bolt holding the stock in place that's loosened up....( its how you change the shims too ) so the directions in your manual will tell you how to check it.

take the stock off ...inspect the spring -- and tighten it back up / and I'll bet that fixes your cycling problem too ( especially if the gun is clean ).

 

[sammyspizza]

Thanks Jim

 

[gaweidert]

Are you using short hulled non brass shells? I recently had a problem on my trusty Remington 870 when shooting clays. Spent hulls sticking in the breech. I was shooting Winchester Super Target 12 gauge.

After a bit of investigation I found that you need to keep the chamber really clean and polished. So I got a 10 gauge bronze brush. Then I wrapped it with 0000 steel wool. Attached the brush to the end and placed the other end of the segment into a drill. Started it up and polished out the breech. Lots of crud came out and it polished the chamber pretty good too. I only takes a few minutes of your time.

The non brass hulls tend to hold their shape after firing and this causes them to stick in the chamber.

 

[sammyspizza]

It's possible that the chamber isnt totally clean. I think it has more to do with the stock or recoil spring. But i'll check the chamber as well. The gun has never had any problems before and it's just strange

 

[Snarlingiron]

The gun has never had any problems before and it's just strange

Not so strange at all. Nothing has problems until it does. All machines (and an auto loading shotgun is just a simple machine) WILL eventually fail. It's never a question of whether it is only a question of when. I bought a used AL390 some years ago. It worked well, but I could hear the recoil spring making a screeching noise every time it cycled. I broke it down and found a very even coating of red rust on everything. Tube, spring, follower, every thing. I cleaned it all up, used a 9mm bronze brush wrapped with 0000 steel wool and polished the tube. Ordered a new spring and it has functioned perfectly since (about 3 years and 10,000 rounds). I now make it a point to take a 10" phillips screwdriver and depress the follower into the tube and lightly spritz with Rem oil on every cleaning.

Beretta 390 series shotguns are among the very best ever made and they don't fail often, but sooner or later the inevitable will happen. Clean up that tube and order a new spring (frankly taking it down makes not replacing the spring kind of silly. Why go to all that trouble and save $20.00?) I'm betting it will return to flawless operation for a long time to come.