non-mim extractor

[sb1010]

I finally got a chance to test with live shells yesterday. It still occasionally stove pipes.

I did notice a scratch inside the receiver. I think the new extractor may rub against the inside of the receiver. I don't feel any drag though.

Have you heard of this?
Does it cause problems?

[Synchronizor]

I finally got a chance to test with live shells yesterday. It still occasionally stove pipes.

If you're regularly having ejection failures even with real ammo, and you're not being timid with the pump, there may be something wrong with your gun, possibly with the action bars or shell latches.

If, as it seems, these stovepipes are caused by the next shell from the magazine, one possible cause could be the action bar that moves the shell latch. If you take your fore-end assembly out of your gun and look at the left action bar, you'll see an angled surface near the front. This is what contacts your left shell latch, and pushes it aside to release a shell from the magazine.

IMG_1545_C.JPG (33.45 KiB) Viewed 2943 times

On mine, this little ramp is about 1/4" long, and it starts 1.25" back from the fore-end tube. When I put the slide assembly in its spot on the action bars, it's 3.75" from the front face of its block to the front end of the ramp.

D1.JPG (23.35 KiB) Viewed 2943 times

How does yours compare? If it was made incorrectly, it could be releasing shells from the magazine early, and causing your stovepipes. It's also possible to adjust your timing by filing this ramp farther forward, but that's not something you want to do on a whim, it's a permanant modification that - by its nature - will make the gun easier to short-stroke, and if done improperly, it can turn it into a single-shot until you buy a new fore-end tube assembly.

The other cause could be your shell latch, but that's harder to check and measure, so I'd suggest having someone take a look at it for you.

I did notice a scratch inside the receiver. I think the new extractor may rub against the inside of the receiver. I don't feel any drag though.

Have you heard of this?
Does it cause problems?

It's normal for the extractor to rub against the receiver when a shell is ejected. As an 870 is broken in, the extractor will wear a notch in the edge of the ejection port to reduce that interference, but even before that, the contact shouldn't negatively affect ejection.

However, if you're using a machined (non-MIM) extractor, you may have gotten one of the ones that wasn't made properly, and interferes more with the receiver. I still don't think that it's enough to cause problems, but it will gouge out the receiver more than a proper extractor. See this thread for details.

[sb1010]

The action bar measures the same as yours.

Today I had slug not eject from the magazine. I worked the slide again and it ejected. I think this happened once before.

I don't think it would be easy to recreate.

Does this point to the shell latches as well?

[Synchronizor]

Maybe, though you might have just short-shucked the gun, or accidentally set the shell on the forward shell latch. I'm still not convinced there's nothing wrong with other parts like your ejector or ejector spring. For all I know, it could be something completely unrelated to what we've been talking about, or even purely user error.

At this point, I'd suggest taking the gun in to get looked at by a professional. There's only so much I can help you with over the internet, and I kind of doubt you'd be willing to travel to Idaho so I can look it over in person.