870 "Jam" - gun defect or feature?

B

Battler

New member
Was out with a friend trying out his new 870 Marine Magnum.

Nice gun.

Bit of a problem - sometimes, the gun would jam just after firing, that is, we would get into a situation where we were racking the slide back; but it would only move a fraction of an inch back, and sometimes have to be wiggled back and forth to open. This was not a stuck shell (Walmart special 7 1/2s), it was real metal on metal stoppage.

Eventually, we found that this was happening when we had rearward pressure on the slide, i.e. from using left hand to push the gun into shoulder.


I'm not sure if this is what caused the problem; but we ended up doing an experiment with the gun, and in comparison to an available Mossberg and a Win 1300. Holding the buttstock against my waist, pulling back the slide hard (but with the gun cocked), pulling the trigger, and holding the trigger down hard. On the other 2 shotguns, the slide would move back the instant the hammer fell, even with the trigger down. The 870 would jam up, until we removed finger from trigger and wiggled the slide back and forth a bit.

Is this normal behavior for the 870, and is our technique just incompatible? Or is there something wrong with the gun?


thanks,
Battler.
 
My 870 "Terrestrial" Magnum used to do the same thing the first time I took it skeet shooting.

The second time I took it out, I can't remember it doing that. But then again, I might have just subconsciously adjusted my technique to suit the gun. I can't really recall.

Maybe your friends will clear up also.
 
I've got a marine magnum and I've never had any problem like you described. Does that one you tried have a side saddle shell carrier on the side? If so maybe the allen screws are too tight and causing the action to get tough.
 
Ineresting post. I have an Express Magnum that does this once in a while to a friend of mine. When I shoot it, it never has a problem but when he shoots, it occasionally behaves this way.
I will have to do your test and perhaps suggest that he try alter his technique a bit.
Thanks,
Mike
 
jadams951 : Gun is bone stock and unaltered.

9mmMike :

Yes, it seemed definitely technique-related - another guy sharing the range could not make it happen, even after we told him to pull back on the forestock while firing, because it was so foreign to him to do so. He would always fire, stop, cycle (even though this was done quickly).


Battler.
 
IMO, the key words here are "New" and "Operator". Try using the strong hand to pull the butt into the pocket, and see if the prob alleviates.

A breakin period will help also, the perts will work polish and the operator will automatically adjust his/her stroke at the same time.

Also, place one drop of CLP on the action bars right where they enter the receiver, and pump a few times. This may help....
 
Dave Mcc:

The lube advice is always good for the longevity of the gun, and breakin good for the action.

And a stronghand pull in DID alleviate it.

However, the "jam" was pure metal on metal. Without letting up, there was no way to rack it without taking pressure off the slide and trying again.

As we don't have another 870 for comparison, is this normal behavior for an 870? Can someone try the test I suggested above? (That is, cock the gun, pull slide down hard while pulliing trigger, do not let up on force, keep trigger down - does slide move automatically? i.e. if you have rearward force on the slide, when it breaks it should jump back).

?

Yes, operating the gun differently would change it; but I don't see this as a desirable feature on a gun that could be used under stress, in a panic where maybe the user applies pressure to rack just BEFORE the trigger breaks, tying up the gun.

Since the 870 has been used as the model of a pump fighting shotgun, I wondered if this is by design, or something broken on this new 870?


Battler.
 
I have a new 870 whick I just shot for the first time Friday. Did not have any problems as you describe. Sounds like a broken gun or you are doing something you shouldn't.
 
Just to be sure, I went and grabbed Frankenstein, MADE SURE IT WAS EMPTY, and tried that. Pulling hard on the forearm and pressing the trigger did not cause any prob, the forearm slid back like it's s'posed to.

I doubt your 870 is broken.I'm inclined to still think a bit of use may fix the glitch.

I do think that this is non typical, and should be dealt with under the warranty.

After the warranty center deals with it, please post something here, I'd like to know the answer. Thanks...
 
OK. I just tested my 870. MAKING SURE THE CHAMBER IS EMPTY I can put a wee bit of pressure on the forearm and pull the trigger and hold. The forearm does NOT come back until I release some pressure. Then it slides back. Holding the trigger back does not seem to matter though. I can do this if I release the trigger as well.
I'm not applying much pressure and I only need to ease off a small amount before the slide becomes "unlocked".
I can do this every time. Is the same thing that you are describing? I would bet it is a sharp edge on something inside the receiver.
When this happens to my buddy, we are shooting and there is an unejected shell in there. Moving the forearm back and forth slightly, clears this.
Like I said though, it does not happen to me while shooting so I am not too upset about it.
Mike
 
9mmMike,

Yes that's exactly the problem. I went to Academy today and tried a 870 as well as a Mossberg pump and they both behaved the same way. A little bit of back pressure on the pump while firing would cause the slide to lock until pressure was released.

I really hope that this isn't a 'design' feature because in a panic situation it could be deadly. The Win 1300 does not appear to do this which would make it a lot more appealing.

Can anyone confirm whether or not this is a design feature? If it is, I would guess that it might be a safety thing to make sure that the bolt doesn't open while the cartridge is firing.

JackSkell
 
On ALL pump shotguns, there must be metal-to-metal contact between working parts in the pump release device. Some guns have a better/different design that releases easier, and many guns are just well broken it, making the release easy.
Take most any pump gun and pull back FIRMLY as you pull the trigger and the release won't release until you back off on the pressure.
The Remington's release is the rear edge of the left action bar engaging the front of the lock bar on the trigger group. Push up on the shell lifter and look inside the left receiver. As you pull the trigger, the lock bar drops, unless you are pulling back on the pump handle. Sometimes these engagement areas are rough, or dry. You can polish the action bar end or the release on the trigger plate, SLIGHTLY. Don't remove much metal or change the angle on either part. Put a dab of grease on the engagement areas.
Shooting will also smooth it up. However, pull back hard and it won't drop. Unless you gun is just factory-defective, this is normal.
 
Thanks for the info, a good cleaning has 'fixed' the 'problem'.

Hopefully I didn't do any permanent damage to the 870 because it was really dry inside. The top of the receiver where the locking block retainer(?) touches has an indentation that looks like a lot of wear for only 20 shots through the gun. Maybe it's normal for an 870?

Thanks,

JackSkell
 
Jack, the 870's lockup is accomplished by the bbl extension and the bolt. Is that what you're talking about?

I strip and detail clean the receiver every 1000 rounds or 6 months, whichever's soonest. A very light lube followed by a wipe off over all the inside surfaces is a good idea. Don't dissassemble the trigger group or bolt unless you're:

A, absolutely sure you can get it back together.

or..

B, willing to slink into a gun shop with a box of parts and ask someone that knows to put it all together for you.

Been there, done that....
 
If I look at the top of the receiver with the bolt back, I can see one particular dent/line that looks like a lot of wear (but it still probably fine) for 20 or shots. It looks like it was caused by the top of the bolt (by the 'nub' that sticks up). Anyway, it's probably fine, after all it would take a hell of a lot of wear to make this shotgun not work.

Thanks for the info,

JackSkell
 
That little notch in the receiver is suppose to be there, that is where the locking block assembly fits in after the bolt closes and locks in with the barrel extension like Dave mentioned.

If you don't have a manual call Remington for one cause you may need it to assist you in stripping it down if not you can always pack it up and take to a gunsmith like Dave metioned.
OTOH when I got my Express a year ago I took it apart and could not reassemble it till I read the assembly instructions
in the manual. Its simple as soon as you learn how to do it.
 
That's interesting because the indent/lip didn't look deliberate enough to be there on purpose (although I believe you), and the manual doesn't go into that kind of detail. I'll take another look.

Took the gun apart last night which was easy. The Rem manual is funny because it warns you to lubricate the gun but then doesn't tell you specifically where to lubricate so I'm just lubing the parts that look like they would rub in normal operation.

Thanks,

JackSkell
 
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