870 Jamming---Please Help Diagnose

[rebelmachine2000]

A friend and I were both shooting informal clays---not keeping score or shooting any kind of organized game. He had an 870 20ga Express and I had an 870 Marine Magnum. Three times out of approximately 200 rounds the action would not cycle after firing---occurred twice on my gun and once on his. The bolt would be jammed shut with the spent shell in the chamber and it would take a considerable amount of force on the forearm to cycle the action. We WERE NOT short stroking the action as we could not pump the gun whatsoever after firing the first shot. The second shot was still fully in the magazine tube.

I imagine that we did something wrong during assembly/disassembly. Or coincidentally damaged our shotguns in the same way somehow. Any ideas ?

[510shooter510]

Did you shoot lots of shells in a short amount of time? The heat may have begun to melt the shell slightly causing it to want to stick. Happened in my 12 ga pump before. Was pumping out a box of 25 fast as I could

[rebelmachine2000]

Did you shoot lots of shells in a short amount of time? The heat may have begun to melt the shell slightly causing it to want to stick. Happened in my 12 ga pump before. Was pumping out a box of 25 fast as I could

We did shoot quite a bit but the initial jamming occurred early in the shooting session. And the jam itself had a mechanical feel to it---if that makes sense.

[wildog8812]

is it a new gun by any chance?

[mydogsmonkey]

sounds like the heat may have got to it, if not perhaps try another brand of ammo, mybe ur 870 just doesn't like that kind

[fusionstar]

My 870 ONLY does that with HIGH Steel cased shells. Like Sellier & Belliot buckshot.
The case expands and is hard to extract. Put a little muscle and it comes out.

what type of shells were you two shooting? My gun loves the walmart 100 pack stuff.

[Dangerous1]

I've had that exact problem with my 870 Express 12ga when it was brand new. It needed 150 shots to be broken in. Since then, it has been flawless.

I diagnosed it to be a sharp edge inside the receiver that eventually wore out through many cycles. It's on the ejector side, where the right side forend rail goes into the receiver. Just take a file to it if you notice burrs.

[510shooter510]

Actually, when I mentioned how this happened to me, I failed to add that this was also with a new gun. Sounds like that may be it

[DuMO]

Possibly a rough chamber. Few people have this problem with their brand new 870s. The jamming usually occurs with the cheaper target rounds (usually found at walmart in 100rd packs). If this is the case and you're interested in polishing it:

http://www.shotgunworld.com/bbs/viewtopic.php?p=1450652#p1450652

I use one section of cheap alluminum cleaning rod with a brass bore brush installed, then wrap the steel wool around the brush and saturate with good gun oil, then go at it. You will not hurt the chamber with this set-up, and it fits in the drill great. I also polish the bolt and bolt stop with oily 000 and then 0000 steel wool by hand. It really smooths out a pump.

[alain209]

use federal it wont jam . its all about the ammo. experienced it with mine using remington ammo but for federal 200 rounds no jam. just personal experience.

[MAX100]

It's a common problem with the 870 shotguns, Polish the chamber. Do a google search there is plenty of info on the subject. Start with steel wool if that doesn't do it get more aggressive with 400 or 600 grit sandpaper. Rig a dowel up and chuck it in a drill and keep it moving in & out. You can use steel wool up into the forcing cone because it's safe but the chamber only with the sandpaper. You may have to do it several times until the problem goes away.

Good Luck! It's well worth the effort to have an 870 reliable with all ammo. I wouldn't want one I had to pick and choose ammo for.

GC

[rebelmachine2000]

Thanks for all the input. Neither gun is new but neither have seen serious shooting 'till now. He was shooting Federal 100 round value pack and I was shooting Winchester 100 round value pack. I suspect that it is because there is some kind of burr as mentioned previously. Hopefully continued shooting will wear the burr down.

Conversely, my gun is a Marine Magnum and this is reputed to be the smoothest operator in the 870 line---confusing.

[MAX100]

People are giving the 870 Express a bad reputation. Its not that common of a problem. It usual only occurs during the break-in period while using cheap bulk ammunition.

It is a common problem with the Express 870s made in the last few years. Do a Google search and see what you come up with. I see these threads with the same problem, on different forums, several times a month. Most doesn't get any better after a break in because many have tight chambers.

Google search: Type in these searches - 870 shotgun shells sticking in chamber, 870 is jamming & 870 is Jamming up...ect Problem after Problem with the 870 jamming. The forums are full of them over the last few years.


GC

[akjunkie]

People are giving the 870 Express a bad reputation. Its not that common of a problem. It usual only occurs during the break-in period while using cheap bulk ammunition.

You are Misinformed. Pass several years Quality Control has gone down at Remington.

the mother of all Shotgun forums: www.shotgunworld.com

the Internet is your friend, try doing some Research.

[rebelmachine2000]

Looks like this is a bigger issue than I originally imagined. I had been indoctrinated into the belief that scatterguns are invariably reliable. Previous posters suggest that this is a problem with the Express guns. Why then is this problem occurring with my nickel plated Marine Magnum ?