non-mim extractor

[sb1010]

Since I see some stovepipes with real ammo. I think it maybe the case with real shells.
I just diagnosed this with a empty shell and a snap cap.

[Synchronizor]

A shell that has just been released from the magazine can cause unreliable or incomplete ejection of the just-fired hull. Once released from the magazine, the next shell will be moving rearward, while the fired hull being ejected will be moving forward, sideways, and rotating out of the ejection port. If the two collide while the fired hull is still partially inside the receiver, the hull may lose the momentum it needs to reliably and positively clear the ejection port.

Once again, lightweight short-base hulls are worse-off in this situation than high-base hulls and unfired shells. Because their center of mass is so close to the base, they eject with less spin and more forward velocity, which makes them take longer to clear the ejection port and creates a larger window of opportunity for interference. Then, if the heavy, rearward-moving shell from the magazine does interfere; it is more likely to arrest the motion of a lightweight hull with less spin and more forward velocity than a heavier hull traveling in a more perpendicular direction.

Also once again, your best bet is to rack the gun hard and fast. When the bolt is brought back faster, the ejector hits harder, and the fired hull clears the ejection port sooner and with more momentum.

That said, if the next shell is released from the magazine prematurely, it has a better chance of interfering with the shell being ejected. This is why I asked if you were seeing this happen more frequently (or only) when using snap caps. If you're using the same A-Zoom aluminum snap caps I use, you should be aware that every one I have was machined with a slightly undersized rim. The 870's shell latches move sideways to release shells from the magazine, so a snap cap with a smaller-diameter rim (especially if the rim has been beat-up and worn down) will be released sooner than a shell with a rim manufactured to spec. This is the same reason these snap caps tend to double-feed.

If you're seeing the same problem with hulls or snap caps with the proper dimensions (and you're operating the slide properly), there are some potential contributors. The shell latches are a big one, if they're bent or worn down in a certain way, they can release shells prematurely from the magazine. Watch them as you cycle the gun, and make sure they're extending and retracting fully and positively, both with and without shells in the magazine.

An overpowered magazine spring can contribute as well. Some folks drop super-ultra-heavy-weight aftermarket magazine springs in their 870s, thinking the extra force will make for more reliable feeding; but shells that are launched from the magazine at higher speeds are more likely to interfere with ejection. If your gun has a super-long or super-heavy spring in it, you should trim or replace it. A pump-action shotgun can only be cycled so fast, and any extra magazine spring power beyond a certain point will do nothing to improve reliability. What it will do is make the magazine more difficult to load, cause more stress and wear on certain parts (not that the 870 can't take it, but why add stress if there's no positive trade-off?), beat up the shells as they're cycled, and encourage malfunctions like miss-feeds or double-feeds.

...Wow, that kind of turned into an essay. I need to get back to my thesis, but I hope this gave you something to go on.

[sb1010]

The magazine spring is the one from the factory.

Should the shell have already ejected at the point the slide is all the way back?
Is it possible for movement to cause the shell coming from the magazine to jump out of place and block the spent round or should the bolt and carrier block this?

The shotgun is not very old less than 1 year less than 1000 rounds. I thought the extractor looked worn though, the edge that catches the shell did not look straight it may be chipped.

I will try and see if the shell latches are damaged or stuck, not completely sure what to look for.

[Synchronizor]

The magazine spring is the one from the factory.

Should the shell have already ejected at the point the slide is all the way back?
Is it possible for movement to cause the shell coming from the magazine to jump out of place and block the spent round or should the bolt and carrier block this?

The ejector will strike the shell, starting the ejection, before the slide is all the way back. The ejector spring starts to drag on the shell rim before that, which can start ejection earlier depending on the shell length & mass, and how fast the slide is being worked. How quickly the shell is ejected will depend on the shell, and how fast you're working the slide. The relative timing of ejection and shell release can vary, since the breech bolt has a little play on the slide assembly when it's unlocked, but the breechface on my magnum 12ga reaches the bit of the ejector that catches the shell right as the shell latch releases the next shell from the magazine. To answer your question, the breech bolt and slide assembly should be far enough back that the shell being released from the magazine cannot be underneath them, so the shell from the magazine will slide underneath the ejecting shell if it hasn't yet cleared the port.

The shotgun is not very old less than 1 year less than 1000 rounds. I thought the extractor looked worn though, the edge that catches the shell did not look straight it may be chipped.

Well, if the extractor is damaged, it probably has something to do with the problem.

I will try and see if the shell latches are damaged or stuck, not completely sure what to look for.

Basically, press on the shell latches, and make sure they move far enough that the little fingers on the end press against the outside of the magazine tube. The shell latches shouldn't wear out after just a thousand rounds, so unless they're defective, or you bent them accidentally at some point while cleaning or disassembling the gun, they're probably fine.

We've been talking about this for a while, but you haven't given much specific detail about the problem. Based on what you've said so far, this could just be the normal result of cheap ammo and improper technique, or a serious malfunction due to multiple damaged or defective components. I could describe things and suggest possible causes until the cows come home, but I really can't give you any specific recommendations without more information. Also, pictures of the parts you think may be damaged or malfunctioning would be helpful.

Exactly how frequently are these ejection failures occurring? Are you seeing this with all types of ammo, or only some types? Low-base/high-base empties, unfired shells, snap caps, some combination? How fast are you working the slide when you get ejection failures? What gauge and chamber length is your shotgun?

[sb1010]

Normally I was experiencing a stove pipe about 1/10 of the time.
This was hi-brass and low brass shells. Some brands of low brass may stick. So I started avoiding them.

A couple of months ago I had a shell stick in the chamber and it was difficult to remove. I had been avoiding the cheap shells but I polished the chamber and I thought I would try again.

The next time I used the gun I had a stove pipe nearly 1/3 of the time. This was with hi-brass Remington and Winchester shells.
A snap cap in the magazine and spent shell in the chamber gave similar results. It seemed something was different now. That is why I created the post. I wasn't sure if an extractor effected ejection that much.

Yesterday I installed a non-MIM extractor. My test with the spent shell and snap cap shows it back to just 1/10 or 1/20. I haven't had the opportunity to test live shells yet. I tried to take photo of the shell latches yesterday. But I think I need a better camera for small parts. The picture was not clear enough.

One time I asked a range master if I was short stroking. He said no but I was operating the slide so fast that the shell didn't have time to leave the port.
Does this sound reasonable to you?

[Synchronizor]

Normally I was experiencing a stove pipe about 1/10 of the time.
This was hi-brass and low brass shells. Some brands of low brass may stick. So I started avoiding them.

A couple of months ago I had a shell stick in the chamber and it was difficult to remove. I had been avoiding the cheap shells but I polished the chamber and I thought I would try again.

The next time I used the gun I had a stove pipe nearly 1/3 of the time. This was with hi-brass Remington and Winchester shells.
A snap cap in the magazine and spent shell in the chamber gave similar results. It seemed something was different now. That is why I created the post. I wasn't sure if an extractor effected ejection that much.

Yesterday I installed a non-MIM extractor. My test with the spent shell and snap cap shows it back to just 1/10 or 1/20. I haven't had the opportunity to test live shells yet.

That's helpful to know, though I would still like to confirm your 870's gauge and chamber length (for now, I'm assuming it's a 3" 12ga gun).

The extractor is an important part of the 870's ejection system. When the ejector strikes the left side of the shell rim, the extractor holds the right side of the rim against the bolt to make the shell rotate out of the ejection port. If the extractor cannot hold onto the rim properly, ejection will be less reliable. It sounds like changing the extractor improved things for you, but there may be something else going on. If the gun is in proper working condition and you're operating it correctly, you really shouldn't see many ejection failures at all, especially with high-base shells.

Have you tested the ejection with an empty magazine? I'd be interested to know how reliably it will eject high- and low-base hulls with the shell from the magazine taken out of the equation. If you have a selection of empty shells on hand, you could also try to find some with different rim thicknesses or shapes, and see if that has an effect.

One time I asked a range master if I was short stroking. He said no but I was operating the slide so fast that the shell didn't have time to leave the port.
Does this sound reasonable to you?

Not really. Remember, the 870's ejection system works on the same basic principle as the semi-automatic Remington 11-48, and (I believe) the 1100 and 11-87 as well. The faster the stroke, the more positive the ejection should be (within the physical abilities of a human user, at any rate). As long as you're completely cycling the action (bringing the slide all the way back until it stops before bringing it forward again), and you're not doing something weird like bringing it back slowly and then slamming it shut as fast as physically possible, you shouldn't be able to "catch" the shell on its way out of the ejection port.

[sb1010]

Without anything in the magazine. A spent shell always ejects. This is true with high and low brass.
It is 12 gauge express 3'' maximum shell length. 28 barrel.
The plug is in it now for hunting restrictions, but that doesn't seem to make a difference.

I don't pull the slide back slowly.

I did shoot a box of high brass federals one in the magazine and one in the chamber. It seems to eject better with those. Those shells cost more than average though.

[Synchronizor]

Without anything in the magazine. A spent shell always ejects. This is true with high and low brass.

Interesting. So the gun ejects all empties properly when there's nothing being fed from the magazine, but a snap cap feeding underneath an empty hull interferes with ejection. If you recall, I explained previously that every A-Zoom aluminum snap cap I've measured (assuming those are the aluminum snap caps you're using) had an undersized rim; and that that could cause them to be released from the magazine prematurely, especially if they had been heavily used, and the rims were worn down further. Those A-Zooms are generally suitable for function tests, but in this situation, those undersized rims throw an unhelpful extra variable into the equation. It would be much better for you to use a real shell for testing instead of a snap cap.

You can do this safely at home with live ammo, as long as you don't chamber the shell, and follow all the standard rules of safety on, finger off the trigger, muzzle pointed in a safe direction, etc. Load the empty hull in the chamber and the unfired shell in the magazine, then test ejection by half-cycling the gun, bringing the slide all the way back but not forward again. This will go through the same extraction, ejection, and shell release events, but the live shell will stay on the carrier, and you can tip it out of the ejection port without chambering it.

Realistic dummy shells would let you test a full cycle,

...but if you don't have any of those, you could also use a fired hull that was originally fold-crimped. Stuff it with whatever random objects you have on hand that will make it weigh about the same as an unfired shell, but won't rattle around loose inside (small metal objects or pebbles, with toilet paper stuffed in above and below to keep them from rattling, as an example), then fold the crimp back in by hand. This won't chamber very smoothly without a proper re-crimping using reloading equipment, but that doesn't matter here. You only need it to feed from the magazine tube, and it should do that just fine.

[sb1010]

I am using A-Zoom.
I saw a video someone using silicone and nuts to fill up a spent shell and making dummy rounds. I think I will try that.

I guess your thinking the shell latches may have a problem if real ammo behaves the same way.

[Synchronizor]

I am using A-Zoom.

That's what I thought. I just tried some moderate-speed, half-stroke ejection tests with my 12ga 870 Magnum, using an empty 2.75" Remington STS target hull (which is a high-quality, well-constructed hull with a short brass base). These were the results:

Empty magazine - positive strong ejection every time
Live Estate 2.75" 00B shell in the magazine - positive strong ejection every time
Well-used A-Zoom aluminum snap cap in the magazine - frequent cases of weak or failed ejection

Also, by deliberately short-stroking my gun with an A-Zoom snap cap in the magazine, I've been able to cause feed malfunctions where the snap cap was not lifted by the carrier when the bolt came back forward, due to it being released from the magazine before the slide assembly was far enough back to engage the carrier dog. Replicating this specific malfunction with a real shell is extremely difficult. The A-Zooms should definitely not be used to test functions sensitive to the timing of shell releases from the magazine.

I guess your thinking the shell latches may have a problem if real ammo behaves the same way.

That's one possibility, but not the only one. The ejector, or the action bars that actuate the shell latches could also cause problems if they're damaged or defective. Or it could be a combination of multiple things.