870 Feeding Issue (Shell stuck halfway in mag tube)

[The_Pretender]

I have an 870 express that I bought solely for the purpose of deer hunting. I was in college at the time, and really wanted a wingmaster (partial to walnut stocks and blued steel) but I ended up with this.

I used it as it was until this spring. I bought a nice walnut stock for it on ebay, and I picked up a chrome bolt as well from gunbroker. I was never partial to the polymer trigger plate/assembly, so I ordered an older aluminum one from gunbroker. I took it all to a smith and had it blued. I hated the original matte finish.

Anyways, I have it all set up now, and am having feeding issues. It is a magnum receiver, and I am using 3" sabot slugs. But I have used these the last few years and I have never had any feeding issues prior to having it blued. But noted, I never put in the new trigger plate until after it was blued.

When I got it back from the smith, there was plenty of residue in the mag tube. I hadn't noticed it before, but I ran a rag down it today to clean most of it out.

When there are 2 shells in the mag tube, the first one cycles just fine. The single remaining shell gets stuck halfway out. This also happens if you only load one shell in the tube. You can pull it the rest of the way out with your finger. I oiled the inside of the tube a little bit, and it worked just fine for a few cycles. Then it went back to the problem.

The brass around the shells are getting some streak marks in them. Almost like when you have grit in reloading dies. So I thought it was something in the tube.
I swapped the spring out with another one, but it still does it.

The only thing I can think of is that the new carrier from the new trigger plate is the culprit. Any ideas? It is rather frustrating. This is the only thing standing between me and the 870 I always wanted.

 

[dfariswheel]

Sounds like bluing residue or light rust in the magazine tube is fouling the magazine spring.
Get a 12 gauge bronze shotgun brush and wrap some 0000 steel wool around it.
Chuck it in a drill and run it up and down the magazine tube at medium speeds.
Don't get it tangled in the shell releases.

This won't need much, just a few passes up and down.
Then use solvent and patches to thoroughly clean out the tube, lubricate, and try it again.

Also, check to be sure you have a 12 gauge trigger unit. It could be a 20 gauge unit.

 

[The_Pretender]

I'll give it a good cleaning, thanks for the tip.

Anyway to tell offhand what gauge the lifter is? The auction stated it was 12 gauge, but I know people make mistakes. I fired it today no problems. The only issue was feeding, and only the single shell. If there were 2, the first fed fine every time.

 

[The_Pretender]

Cleaned it all out as prescribed, and have cycled rounds through 60 times now. Not one issue. Hopefully it stays this way.

Thanks for the help.

 

[The_Pretender]

Well, it went about 80 times with no hangups. I set it down for a while, and when I came back to do some more, it got stuck again. But only on the very first cycle. After that it works every time. If I leave it alone for a while, it does it again on the first one, but after that it's ok.

I figure letting it sit gets it caught up. I'll give it another cleaning later. I'm positive that foul-up from bluing was the culprit now.

 

[dfariswheel]

Your next step is to clean out behind the shell releases.
It sounds like the re-finisher didn't do a good job of "killing" the bluing chemicals or cleaning everything up.

DO NOT remove the shell releases. These are staked in place and aren't removable unless you have a special tool to re-stake them in place.

Disassemble the gun and protect the wood.
Get a can or two of a gun scrubber spray and very liberally flush out the back sides of the releases by spraying into the front and sides.

Dry thoroughly then spray in a gun lubricant and drain out the excess. Rem-Oil seems to work well.
Test the releases by pushing them toward the receiver walls.
They should move freely with strong spring pressure and return to position.

Also, check the magazine follower to insure it's not bulged or damaged. It should slide freely down the magazine tube.
Make sure the spring isn't kinked or damaged, and that it's the right length.

 

[Youngster]

What's your mag follower looking like? If there was as much grit as it sounded like in there it might be chewed all ragged and catching on stuff.

While you're in there you might want to take a second look at the inside of the mag tube {with a flashlight if possible} and also check to see if the spring's still looks good.

 

[Six]

DO NOT remove the shell releases. These are staked in place and aren't removable unless you have a special tool to re-stake them in place.

But if they do come off (as one of mine did in my zeal to get to every last speck of dirt), it's not a big deal. The gun works fine even if the shell latches aren't staked in place.

 

[The_Pretender]

I cleaned out the shell releases, and double checked the magazine tube. I have a bore light, and when looking down it it looks like a shot barrel. Clean and shiny.

I figure the shell releases can't be an issue as the shell is coming out and they are out of the way at the time.

Upon inspection of the magazine follower, it has some light scratches on it, and feels rough/chewed a little around the base. I've ordered a replacement aluminum one from midway. Perhaps that could cause it to drag somewhat on occasion?

My only thing is, since it doesn't happen every time, it has to be something with a little give. If the new follower doesn't help I really am at a loss. The old one moves freely in the tube without the spring. The spring isn't an issue as I have already tried a different one and had the same problem.


Also, before I cleaned the tube out it happened every time, unless there was a lot of lubricant. The damage may have been done by that point to the follower, and once all the grim was removed, it still happens every so often.