870 Feed Jam cause?

[1911user]

I had several failure to feed jams on my 870 (express) today. The shell to be loaded was not lifted quite high enough to line up with the chamber and it caught underneath the chamber. Each time it happened I pumped back and forward again then it fed fine. I suspect I was short stroking the action but I've never had that problem with other pump shotguns. I was trying to shoot fast each time it happened. I can work on a full pump stroke each time, but is there anything else to check? I pulled the trigger group and couldn't see any problem with the lifter movement.

The only recent change on the 870 was adding a Choate 3-shot mag extension but I doubt that's a problem since a shell was always available at the right time.

 

[slopemeno]

I always try to make sure the round is inserted well past the two shell stops. Nothing worse than the round popping past and tying everything up.

I think youre short-stroking, as you thought. You might get some practice on a falling plate rack, or pepper-poppers. Your local action shooting league will be the place to start looking. I think you'll find action shooting will help you find the happy medium between pure speed and accuracy, as well as some exposure to more advanced shooters who will coach you.

 

[9mmMike]

I had this problem on an 870 as well. It was as if the shell did not come up fast or far enough and the bottom edge was sticking. It reminded me of a 1911 that needed a sever ramp polishing except there was no ramp to polish.
A slight "backing-up" of the pump handle allow it to raise the rest of the way and feed OK.
Also if I slowed down, it was hard to recreate.
To start, I would take the extension off for a test run. I so not think this is the cause but if you just added it and the problem showed-up, it makes some sense to at least run a test without it.
I would also suggest that you drop the trigger group and spray it clean before soaking it with rem-oil and shaking off the excess prior to reinstallation.
I had a '55 WM that did this and it not go away until I swapped to a later style flexi-tab bolt assembly and trigger group. Runs fine now.
Good luck with yours. I know it is frustrating and it seems to be rare as I did not have much luck finding other instances on any of these very fine boards that are filled with decades of wisdom.
Mike

 

[1911user]

You might get some practice on a falling plate rack, or pepper-poppers. Your local action shooting league will be the place to start looking. I think you'll find action shooting will help you find the happy medium between pure speed and accuracy, as well as some exposure to more advanced shooters who will coach you.

Funny you should mention that; my first 3-gun match is Saturday and the primary reason for adding the mag extension.

9mmMike, I'll clean and lube the shell lifter pivot points. It was frustrating to have a pump shotgun jam repeatedly even if it was easy to clear.

 

[Rogmatt]

I have a couple of 870s and I have dicovered the following:
If you work a pump action too slow, you have a higher chance of having a jam. I have had 2 misfeeds with one of my 870s, both times they were pumped slowly.
Pump actions work better & more reliably if pumped fast & firm.

 

[9mmMike]

I have a couple of 870s and I have dicovered the following:
If you work a pump action too slow, you have a higher chance of having a jam. I have had 2 misfeeds with one of my 870s, both times they were pumped slowly.
Pump actions work better & more reliably if pumped fast & firm.

When my 870 had this problem, faster was worse. If I slowed down just a wee bit, the problem went away. That was not the correct fix but those were the conditions.

Mike

 

[1911user]

9mmMike,

I shot the match today and still had a few feed jams out of 30 shots. I cleaned and lubed the shell lifter parts but that didn't seem to help. I'm starting to think the mag spring that came with the choate extension may be the cause (or at least exposed the problem). From the sound, it is obvious the shell is being released from the mag tube with mucho pressure behind it. I'm wondering if the shell isn't flying back then bouncing forward due to the stronger mag spring.

Could the mag spring be too strong? I know the normal problem is too little pressure, but

 

[9mmMike]

I had the same thought during my trials with this problem. In fact, I also thought that perhaps I was shucking too fast and the shell might actually be bouncing off of the top of the receiver and knocking the lifter back down enough to cause this problem.
It is very aggravating and, until you posted it, I thought I was the only person on the planet to encounter it.
I also replaced all the springs in my 870, from the mag to the trigger group and nothing fixed this problem until I converted the gun from the original trigger group to a flexi-tab group, including a flexi-tab-style bolt and carrier.
Now your gun is already there so the only thing I can offer is perhaps a trigger group swap to see if the trouble goes away.
I also swapped the lifter, twice, on the old group to see if it helped. It did not.
This problem seems to be so rare that nobody knows how to fix it.
Mike

 

[Dave McCracken]

If it helps, I have a spare carrier sitting around. Let me know if you need it....

 

[Fred Fuller]

1911user,

Was the gun running OK before you added the extension? Does it run OK with the last 2-3 shells in the extended magazine and only jam when the extended magazine is full? That would sound like a mag spring issue...

Did your gun have dimples in the mag tube that were removed?

When you cleaned the trigger plate assembly, did you make sure to clean out the recesses behind the shell stops on both sides of the receiver as well? It's not necessary (in fact it's a bad idea) to remove the shell stops to do this, spray cleaner should work OK with a little help from an old toothbrush carefully applied if necessary.

Inquiring minds want to know...

lpl/nc

 

[1911user]

1911user,

Was the gun running OK before you added the extension? Does it run OK with the last 2-3 shells in the extended magazine and only jam when the extended magazine is full? That would sound like a mag spring issue...

Did your gun have dimples in the mag tube that were removed?

When you cleaned the trigger plate assembly, did you make sure to clean out the recesses behind the shell stops on both sides of the receiver as well? It's not necessary (in fact it's a bad idea) to remove the shell stops to do this, spray cleaner should work OK with a little help from an old toothbrush carefully applied if necessary.

Inquiring minds want to know...

lpl/nc

I only fired it a few times fast before adding the mag extension so I'm not completely sure it was OK before, but I never had this failure with the original setup. I will try removing the extension and using the original spring and follower.

I removed the tube dimples by using a socket that was almost the same size as the mag tube interior and then using a punch to smooth out what remained of the dimples. It seemed smooth inside but I'll recheck it.

To be clear, I don't get this feed jam if I cycle at medium or slow speeds; it only happens on fast cycling.

This afternoon, I did an experiment of loading the mag tube full then cycled them fast trying to be sure that I didn't short stroke it. I loaded it 5 times (7 shells each time). I had 1 failure on the first round out of the mag but I'm not confident of a full pump for that shell. I had 2 failures with the 3rd round out of the mag. That's signifigant because that's when the follower would be moving through the area where the extended mag tube meets the original and where the pressed-out dimples are located. When I was adding the extension, the new follower didn't slide freely so I chucked it in a drill and turned it down until it slid smoothly (including the area where the dimples were). The other 2 failures were from the last shell out of the mag tube.

I haven't cleaned the shell stops yet, but will pull the trigger group and check them.

I mentioned this problem on Brian Enos forum last night and one person previously had the same problem. When he called Remington they sent a new "feed dog" which solved his problem.

I've read where people used a tool to "bell" the end of the original mag tube to help funnel shells coming from the extension tube. I may need to do that also. Is there a substitute for this tool?

 

[Fred Fuller]

Sounds as if you are on the way to a solution then. It's better IMO to work from the muzzle back on a magazine/feeding problem. I'd say the first thing to do is to make sure the dimples are well and truly gone. It doesn't take much in my experience to cause tieups in the area where the dimples were. It's my preference to remove them completely if I deal with them at all. You can handle yours however you want but you need to be sure they are not the source of the problem. Some experimentation with the magazine and extension assembled without the mag spring and follower installed might help indicate where the problem is, if indeed that's the source of trouble. Drop in a round, and tilt the gun up and down while the shell slides back and forth. See if it hangs up or slows down anywhere along the way.

Turning down the follower doesn't help the case heads get through... that doesn't sound good to me. Sounds like there is still enough dimple material in the way to cause trouble if teh follower wouldn't go through easily. My guess is it's more likely the dimples than the mouth of the original mag tube needing to be 'belled.' It might be that's the case, but i haven't run into that particular problem in the course of installing dozens of extensions. Not to say it is impossible, just that it doesn't happen as often as trouble with dimples.

And it might be a worn or damaged carrier dog, spring or follower. Can't rule that out either without seeing the gun. Make sure these parts function freely and are properly clean and lubricated in your gun. But clean up the potential mag tube problem first...

lpl/nc

 

[9mmMike]

A "feed dog"? Do you suppose that's a carrier dog?
I replaced that as well. It was attached the second (and third) lifter that I tried. It's worth a try though.

 

[1911user]

Lee,

The follower that came with Choate extension kit would not even fit into the mag extension (let alone slide freely) until I turned it down some. I removed just enough material so it would slide freely in the extension. That was enough to slide freely in the main mag tube also.

This may have been an older stock mag extension kit. It came with a letter stating 1994 AWB limitations for the extension. Also, the screw that holds the mag clamp wasn't long enough to get even one thread into the nut. It was a known problem that I thought they would have corrected by now. I used a longer bolt with the clamp and it works fine.

 

[9mmMike]

Any progress with this problem? Please keep us posted.

 

[1911user]

Any progress with this problem? Please keep us posted.

How about an update 2 years later??

I put the 870 in the back of the safe and mostly forgot about it until a few months ago. The problem was the shell sometimes not being lifted fast enough to feed. The solution appears to be a new carrier dog follower spring. I ordered one from Brownells. After installing it, I haven't been able to jam the 870 again even when pumping very fast.

The choate mag extension was not a problem. The magazine follower from choate was oversized from the factory, but I'd turned it down so that wasn't an issue. I replaced it with one from scattergun technology anyway.

Now the 870 runs and will soon join me at the skeet field.