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kotengu
October 08, 2014, 19:59
<iframe width="560" height="315" src="//www.youtube.com/embed/Ae6kvStq7d8" frameborder="0" allowfullscreen></iframe>

I've been having a new problem with what I thought was "short stroking" my 870 while trying to shoot faster. I had my daughter video me tonight to make sure, and I just don't see how I could stroke the pump any farther or harder. Shell #1 loads and shoots fine. Shells 2 and 3 are the failures I'm describing - I thought it was short stroking, but maybe it's some other kind of failure to feed. Shots 4, 5, and 6 were normal, with the exception of shot 5 throwing a fireball out the ejection port. I assume this is the cheap ammo I'm using (for the first and last time tonight) as it happened several times and I've never seen it before.

After shot 7 I really did short-stroke to the point where it didn't eject, and I caught it and fixed it on the fly. Shot 8 cycled normally.

The video is normal speed through the loading (I'm new to load 2 and figured I could use the practice), and switches to slow motion as soon as the shooting starts. I'm mainly concerned about figuring out what's causing the failures to feed, but if anyone can offer tips on my loading I'd appreciate all the help I can get!

KoKodog
October 08, 2014, 20:42
the dirty shells are a clue, excess nitro-cellulose in cheap powder

you are not short stroking every time

shell latch is not releasing the shell from the tubular magazine

start with a complete tear down and cleaning

it may just be dirty

if it still does the same thing after cleaning try replacing the shell latch or shell latch spring

Illurian00
October 08, 2014, 20:51
Take a look at the shell latches. See if they appear loose, or out of position. They may have to be 're-staked'. Most any working smith will have the tool to do the job. Simple fix.

kotengu
October 08, 2014, 20:55
Shell latches appear firm and solid, and everything works perfectly slowly - or even medium speed. It's only when I approach 0.5 second splits that it starts to act up. Same failures happen with Federal #8, and have happened with multiple extension tubes and springs.

You would think if it were a loose shell latch it would show up all the time - not just fast.:confused:

idsubgun
October 08, 2014, 21:06
Kuhnhausen has a great gunsmithing book the covers the Remington 870, 11-87 and 1100. I'm not home so I can't look in mine to see what it says, if anything, about your problem(s).
Anyhow, it's a great resource if you're into gunsmithing Remington shotguns.

SAFN49
October 08, 2014, 21:25
Shell latch is held in by the trigger group. Does not really need to be staked.
Just makes it easier to clean and reassemble when the trigger group is removed.

Looks like an issue with the ammo.

kotengu
October 08, 2014, 21:33
I should have also mentioned that this is random at speed. I made it sound like it was always shells 2 and 3, but it's not. If I slow down just a fraction of a second it goes away.

I'll have to get that Kuhnhausen book - thanks for the tip. Up until today I thought there was nothing to gunsmith on an 870...

Illurian00
October 08, 2014, 23:10
Check the magazine tube, make sure it's clean.
Also the the mag follower. Their are upgrades for the follower.

Mayhaps the timing of the shell carrier ?

SAFN49
October 09, 2014, 00:06
I should have also mentioned that this is random at speed. I made it sound like it was always shells 2 and 3, but it's not. If I slow down just a fraction of a second it goes away.

I'll have to get that Kuhnhausen book - thanks for the tip. Up until today I thought there was nothing to gunsmith on an 870...

Get an Ithaca with no disconnector, much faster.

croftonaviation
October 09, 2014, 07:23
Has this happened with different types of ammo? I had some of the super cheap, aluminum base Winchester and it flat locked up my 870. I switched to anything that was brass and never had another issue.

Good luck

kotengu
October 09, 2014, 09:24
At least two different types of ammo: Federal and some cheap Walmart stuff. I think the Federal is brass-based, but I'll have to check.

Mag tube is clean. Happens with three different mag extensions and three different springs. The one on there now is a Nordic +5 with the spring trimmed at 12" past the end (as they recommend). Happens with two different followers - both "upgrades".

What really has me baffled is that it's only when shooting fast. If I back it down to 0.75 second splits or so the gun cycles flawlessly. Is it possible to "outrun" an 870?

MAINER
October 09, 2014, 09:46
Any problem without the extension tube? Have the "Dimples" been removed so they don't interfere with the follower?

Just a couple thoughts. I have a +3 tube on mine and no such problems with it, but can't say I've tried speed shooting with it.

tac-40
October 09, 2014, 18:21
I would say that the problem is with the mag tube spring. You are cycling the action faster than the rounds are being pushed down the tube. I think you need a stronger mag tube spring. To test this out, put a shorter extension on it with a longer spring and shoot it like you mean it. If it cycles fine, then the spring is the culprit. If it fails to feed:

http://www.mediabistro.com/fishbowldc/files/2011/07/46246205_1caa2bcb16.jpg

Bruce Allen
October 09, 2014, 20:10
Any problem without the extension tube? Have the "Dimples" been removed so they don't interfere with the follower?

Just a couple thoughts. I have a +3 tube on mine and no such problems with it, but can't say I've tried speed shooting with it.

Me, too..
I have shot my 870 at speed at matches and loaned it to others that shucked it faster than me with no problems.

Regardless it should function fine if the spring tension is proper for the mag size one would think.

idsubgun
October 09, 2014, 20:22
I'll have to get that Kuhnhausen book - thanks for the tip. Up until today I thought there was nothing to gunsmith on an 870...

Well, there usually isn't much gunsmithing to do on 870's but they do have quirks sometimes. I'm a huge fan of 870's. I have 4 now and have owned a dozen or so. I know there's other shotguns out there, but the 870's do what I want a shotgun to do, so why switch?

BTW, the part the breaks most on Remington shotguns are the firing pins. Grab an extra or two for your stash. The 870, 11-87 and 1100 all use the same firing pin. Good trading fodder in the post-SHTF world. ;)

kotengu
October 10, 2014, 06:08
Thanks guys. The spring is pretty stout, but I'll sure try a stronger spring and see what happens.

And get a few spare firing pins. :whistling:

tac-40
October 10, 2014, 19:52
Just remember, that spring has to move almost a half box of 12 ga when the mag is full. That is a lot of inertia to overcome (approx 1 lbs).

Bruce Allen
October 11, 2014, 13:32
Matt:
I found a video that has some interesting info. The video is not well done but the guy has a novel approach to diagnosing fail to feed problems with the 870.

In it he mentions the "tabs" on the slide arm that get worn and do not activate the shell release from the magazine.

Hope it helps.

http://www.youtube.com/watch?v=Xg2YxZ32u70

kotengu
October 12, 2014, 09:10
I would say that the problem is with the mag tube spring.

We have an apparent winner. I installed the 6rd (total) tube with the 7rd spring and it cycled fine - for 6 rounds anyway. I'll order a new spring from Nordic and try it with the 9rd tube.

Funny - "conventional internet wisdom" is that you need a strong spring for a semi-auto shotgun, but that it can be extremely weak for a pump. 12" of free length (longer than the tube) should have been plenty.

I guess that's what I get for listening to internet wisdom. Or maybe I'm approaching semi-auto speeds with my pump! :devil:

KoKodog
October 12, 2014, 12:09
the problem very closely parallels the Glock mag issue whereas ;

you look at the 33 round 9mm mag and the 22 round 40 S&W mag

Glock engineers chose the capacity of each mag based on the physics of a springs ability to lift " W " amount of weight in a vertical column with " X " amount of force in " Y " amount of time based on a friction factor of " Z "

they calculated many possible outcomes of reliability by varying the inputs for each factor and came to the best choice that would cover the greatest change in variable inputs to reach a maximum reliable capacity

for the 9mm they chose a max capacity of 33 rounds
for the 40 S&W they chose 22 rounds

SAFN49
October 12, 2014, 13:50
Or maybe I'm approaching semi-auto speeds with my pump! :devil:

You should be able to pump a pump faster than a semi auto. If you are shooting nothing but 2 3/4" loads find a 870 with a 2 3/4" only receiver. It takes much less distance to stroke one of these than the bolt travel on 3" semi.

gunplumber
October 12, 2014, 15:27
I would say that the problem is with the mag tube spring. You are cycling the action faster than the rounds are being pushed down the tube.

This is what I was thinking. Also, there are different diameter springs. For example, a wolff spring binds with a remington extension. Can't tell what you have on the end there, but I suspect it's not a Remington.

The carrier dog pushes the shell stops. Some people excessively polish these surfaces in the mistaken belief it will be "smoother". But what it does is diminish the degree of movement in the stops.

DC
October 13, 2014, 08:30
I've had this happen and odd as it sounds, the problem was unburned powder underneath the ejector and ejector spring magazine. I was using some off brand shells provided at a sporting clays fundraiser event. I guess the little pieces of powder made the ejector stick out just enough that it wouldn't let rounds feed cleanly (no pun intended). You couldn't tell it was sticking out by looking but once the powder was removed, it's been fine ever since.

Honestly, such a simple problem with such a simple piece of flat steel made me reconsider what I always thought was the most reliable shotgun out there.

idsubgun
October 15, 2014, 01:07
Honestly, such a simple problem with such a simple piece of flat steel made me reconsider what I always thought was the most reliable shotgun out there.


You shoot off brand ammo, which is apparently dirty, until the shotgun is too dirty to operate, and you blame the firearm when it fails to operate correctly?

0302
October 15, 2014, 08:47
i have a winchester 1300 that initially would not feed the round from the tube into the receiver without shucking it twice. i put a new spring in the tube but same results so i nested the springs together and put both in the tube & now it feeds like a champ. it almost like it reads my mind its so fast.

kotengu
October 17, 2014, 22:32
OK - new spring came in, and I trimmed it to leave 18" of free length past the end of the tube (as opposed to 12" that I used to have). It was all I could do to get the cap back on. The shells slide freely in the magazine tube with no spring in it.

It fails more frequently now, but now the hammer fails to cock (or maybe there's some other trigger problem - it doesn't click or move when I pull the trigger) when the round fails to feed. I used to have a fully functioning trigger pull on an empty chamber before.

I took a closer look at the trigger group and can find no problems. Shell latches look good and are well staked. Shell lifter operates perfectly, and I cannot recreate this problem either slowly or even quickly but with an empty gun - I tried dry firing and cycling quickly while videoing in the ejection port. Everything runs normally.

WTF :? This is such a simple machine I can't for the life of me figure out what could be different. Maybe I'll swap some more tubes and springs tomorrow and see what happens.

Bruce Allen
October 17, 2014, 22:50
You got me thinking about the spring length.

So I removed the 3 round extension from the recently liberated 870 and it extended almost 14 1/2 inches out of the original mag tube.

When reassembling the mag tube it is not at all hard to compress the spring and screw the extension into place.

SAFN49
October 17, 2014, 23:08
Try a different trigger group.

kotengu
October 18, 2014, 20:16
More trials today. I detail stripped the trigger group, receiver, and action bars, and everything looks good.

Nordic +5 extension with 18" free spring length, loosened one full turn and clamped to the barrel (recommended way to minimize barrel stress from the clamp) gave me FTF on round 3, 5, and 7:

<iframe width="560" height="315" src="//www.youtube.com/embed/piyJs6APgzY" frameborder="0" allowfullscreen></iframe>

Same extension and spring with no clamp, and tightened fully (thinking the gap between the extension and the factory tube and/or misalignment of the extension might be causing my problem. Gave me FTF on rounds 2, 3, 4, 5, and 6:

<iframe width="560" height="315" src="//www.youtube.com/embed/DDKZB30o-h8" frameborder="0" allowfullscreen></iframe>

So I revisited the 6rd tube with the 7rd spring to see if it was a fluke last time. Flawless action with 0.41 second splits:

<iframe width="560" height="315" src="//www.youtube.com/embed/LZ58pcXiLKw" frameborder="0" allowfullscreen></iframe>

Same spring with a 7rd tube gave me FTF on rounds 3 and 4:

<iframe width="560" height="315" src="//www.youtube.com/embed/R2JWdJLWaAs" frameborder="0" allowfullscreen></iframe>

It HAS to be tube and/or spring related. The spring on the +5 extension is hugely stronger than even the 7rd spring in the 6rd tube. There are no burrs on the end of my factory tube, and rounds slide freely inside the tube even without a magazine spring. I stacked 6 rounds in a line outside the tube just to be sure, and the 6th round sits well past the factory tube/extension transition. You would think that if the transition were at fault the first round out of the 6rd tube would FTF - or the last five rounds out of ANY of the tubes would feed fine.

WTF?!?!?!?!?

SAFN49
October 18, 2014, 21:04
Just one of those ghosts in the machine. Stick with the 6 rd tube and 7 rd spring.

Beckman
October 19, 2014, 03:43
Shell latches appear firm and solid, and everything works perfectly slowly - or even medium speed. It's only when I approach 0.5 second splits that it starts to act up. Same failures happen with Federal #8, and have happened with multiple extension tubes and springs.

You would think if it were a loose shell latch it would show up all the time - not just fast.:confused:I've had a problem with an 870 that sounds exactly like yours. I've replaced the Foreend Tube Assy (#28) and a gunsmith said that the problem was with one/both of the action bars (#55,56), which he replaced. I tried a slightly stronger spring. None of that worked.

One thing that I did notice was that for diagnostic purposes, after firing, I would only open the action without closing it, then check to see whether a new shell was on the carrier. I did that at the same speed as when I usually cycle -- but only half the cycle.

The times when no shell was on the carrier, I noticed that the shell in the magazine -- the one that failed to feed -- was behind BOTH the right and left shell latches. I believe that this was significant.

However, I'm not sure why it does that or how to fix it. My current theory is that the shells' momentum during recoil moves them forward in the tube while I cycle the action. If the action is cycled at a certain time, then the shell gets caught behind both shell latches. It's not specifically a matter of outrunning the feeding. It's a matter of timing, although it's not a problem if the cycling is slower.

That's my latest theory, anyway, but I haven't worked on it in a while.

You may want to check if your 870 does the same thing. Maybe it'll help you diagnose your problem if yours does the same thing. Good luck.

http://www.gunpartscorp.com/Manufacturers/Remington-33454/Shotguns-37896/870-41213/PartsList-34304.htm?page=7

http://www.gunpartscorp.com/pub/schematic/Remington_870_schem.jpg

IA_flyboy
October 20, 2014, 19:44
I use a different gun with my Nordic Components extension tube (Benelli Nova) so my input is limited to the NC tube side of the equation.

I seem to recall that when I bought my +5 tube from them that there was a specific call-out for a "low-drag" mag tube follower to be used when the mag tube was over a specific length (I believe it was at +5 or greater). I can't find reference to that in the product descriptions on their site tonight, however, so I can't pinpoint exactly where that came from for you. They're pretty proud of that little piece of hard-anodized aluminum though... :?

kotengu
October 20, 2014, 22:10
I actually started with the Nordic follower in the +5 tube, but had some sporadic hangups when loading/unloading (load 2 practice with dummys) so I switched to my old Wilson Combat follower, which slid freely in the tube. Maybe I should revisit the Nordic follower and figure out exactly why, how, and where it was hanging up...

DC
October 21, 2014, 13:28
You shoot off brand ammo, which is apparently dirty, until the shotgun is too dirty to operate, and you blame the firearm when it fails to operate correctly?

if two flakes of unburned powder make a shotgun fail, then yes.

ByronF
November 02, 2014, 17:34
I also think it is significant that the shell in the magazine is latched behind BOTH latches. The left (rear) latch is deployed, retaining the shell when the action is locked. The right (front) latch is retracted out of the way of the shell.

1. As action moves rearward the right latch deploys in preparation for stopping the second round in the mag tube. In this way the magazine will release just ONE shell instead of the entire magazine contents.
2. When the action is almost completely rearward the left latch retracts, allowing the first shell in the mag tube to pop back onto the carrier. The second shell in the tube is stopped by the right latch that popped out in the first step.
3. The action reaches full rearward position and is then slid forward. Very soon the left latch deploys again, but the next shell in the tube is still held by the right latch.
4. As the action nears battery the right latch tucks back into the walls of the receiver, and the shell in the mag tube pops rearward maybe 0.100" until it is arrested by the left latch. So the latches hand off control of the next round on deck.

Probably not telling you anything you haven't already learned since this has been vexing you for a while. Is the aluminum Nordic still all pretty on the OD, or chewed up from passing the transition from tube to extension?

Byron

kotengu
November 03, 2014, 14:11
OD of the Nordic is a little banged up from where I smacked it on the concrete several times recently by mistake, but it's all cosmetic damage.

You are 100% correct on your shell latch descriptions, and I've become intimately familiar with them while fighting this gremlin. I can find no problems with my shell latch action during slow and/or partially disassembled cycling. I cannot really watch them in detail while cycling fast though.

I played with followers and mag tubes some more and did find I have a very slight narrow or rough spot about halfway down my FACTORY tube (not the extension). I tried polishing it with a drill mounted JB paste, but didn't change anything. Only the Nordic (largest of all OD of the followers) hangs up here, and if any pressure at all is put on it, it slides free. There's nothing visible in the tube, but it's all I can come up with. Anybody know how it's attached to the receiver? Maybe silver solder?

gunplumber
November 03, 2014, 14:26
yes, it's soldered. I remove dents with a tapered mandrel, and hammer the outside of the tube with a small brass hammer to lift the dent. Your paste isn't aggressive enough. Slit a dowel and put some 100 # sandpaper around it.

TOWS220
November 03, 2014, 18:23
Still have trigger reset issues?

kotengu
January 25, 2015, 13:46
I gave up on this for awhile, but I just can't let it go. I did find a VERY slight restriction in the middle of my factory mag tube, so I turned down a piece of black pipe to 0.920" OD so it would just barely fit in the end of the mag tube. I then turned down an extra 0.010" for 3" on the end and cut a slit so it would hold sandpaper. A lot of time and oil later, with 320 and 600 grit paper, and the mag tube is uniform and very smooth.

http://i902.photobucket.com/albums/ac224/mcstennett/IMG_1200_zps6ca45493.jpg

That didn't fix it either. I did find that after shooting, and when I experienced the FTF, the next shell that SHOULD have cycled was held by the right (secondary) shell latch - not the left (primary) shell latch like it should have been. I played with the shell latch geometry awhile and did find a worn screw holding my side saddle on that MIGHT have let the right shell latch move backward a little and made it easier for it to catch the rim of the shell. Removing the side saddle and reinstalling the factory trigger pins (with no wear at all) changed nothing. The shell latches function completely normally and have no debris or extra wear.

So I fabricated a bracket to mount my iPhone underneath the shotgun and take a 120 fps video of the failure happening.

Below is the tube just before firing:
http://i902.photobucket.com/albums/ac224/mcstennett/PreFiring_zps63e0b041.png

And below is the tube just after firing:
http://i902.photobucket.com/albums/ac224/mcstennett/PostFiring_zps59194625.png

The only thing it can be is the inertia of the 9 shells in the tube being pushed forward (or more accurately, staying in place while the shotgun moves rearward). I have a +5 extension and 18" of free spring length outside the tube. The magazine spring is VERY strong, and yet it happens unpredictably whether there's 9 rounds in the tube or 3.

The physics make sense - but what I can't figure out is why I seem to be the only guy having this problem?!?!?!?! Why does everyone else's shotgun work fine, even with less magazine spring force?

kotengu
January 25, 2015, 14:14
The times when no shell was on the carrier, I noticed that the shell in the magazine -- the one that failed to feed -- was behind BOTH the right and left shell latches. I believe that this was significant.

However, I'm not sure why it does that or how to fix it. My current theory is that the shells' momentum during recoil moves them forward in the tube while I cycle the action. If the action is cycled at a certain time, then the shell gets caught behind both shell latches. It's not specifically a matter of outrunning the feeding. It's a matter of timing, although it's not a problem if the cycling is slower.



I just brought this back up so you could say "I told you so". Several others mentioned inertia, but i just couldn't figure how there could be so much inertia the shells would stay out until the action was all the way cycled (when the primary latch lets go). Bringing the secondary latch into the equation makes perfect sense.

Now the hard question - WTF to do about it? And why doesn't it happen to everyone?

What's the feeding mechanism on a Benelli Supernova? That seems to be the latest favorite in the pump shotgun games - but from what I've read it's mostly because it's easy to load.

Bruce Allen
January 26, 2015, 01:28
The only thing it can be is the inertia of the 9 shells in the tube being pushed forward (or more accurately, staying in place while the shotgun moves rearward). I have a +5 extension and 18" of free spring length outside the tube. The magazine spring is VERY strong, and yet it happens unpredictably whether there's 9 rounds in the tube or 3.
Please forgive my uneducated and simplistic mind but it seems to me if the shells are not being held in their proper place by the spring pressure don't you need a stronger spring and/or a way to reduce the recoil of the shotgun?

Is that the only shotgun you have and is it the only one with that problem?

My point is wondering is it the shotgun or you or both together?
I am also wondering does it malfunction with others shooting it?
Could it be a person's body mass amount effecting the recoil travel more or less depending on the amount of mass a body has?

SAFN49
January 26, 2015, 01:52
He must be limp shouldering it. :uhoh::wink::D

Have you tried lighter loads? Like 7/8 ounce or 1 ounce?

kotengu
January 26, 2015, 07:25
Could it be a person's body mass amount effecting the recoil travel more or less depending on the amount of mass a body has?

I have wondered the exact same thing. Maybe it's something I'm doing - timing/technique of the pump, recoil absorbtion, etc. Or maybe the guys doing this are using light/reduced loads. They are playing gun games and that is a very common practice.

This is the only shotgun I have. You can see in the videos I don't move much when shooting, but I am a fairly little guy - who knows?

Mebsuta
January 26, 2015, 08:24
Are you pulling back on the fore-end when you have it shouldered, before firing? I think some people say to do that for speed so it releases itself, but I get hung up when I try that with pumps.

I try to pull it back with the buttstock into my shoulder so I don't hold it too loosely and get beat up, at the same time not pulling back on the slide.

I am not gamer or competitor, am all-around bad shooter and just blast casually at clay things, but I have to be deliberate with the 870 or get hung up.

Personally I like the Maverick 88 a little better than the 870 for the casual blasting I do, although I like both.

kotengu
January 26, 2015, 13:39
I am putting rearward force on the forend before firing, and have no problem with the system unlocking and cycling when it fires. The only problem is that a shell is not released and I end up with any empty chamber!

I did have an interesting comment from another (competition) forum I thought I'd share here:

I just saw this thread. Indeed, it does sound like your shells are "moving forwards" in the magazine tube under recoil due to their inertia. This phenomenon is actually quite well known to Remington - it is called "shell surge", and is the result of taking a gun designed for duck hunting and adding a magazine extension to make it "tactical". A stronger magazine spring is only a BandAid. And the folks who claim not to have a problem are often MUCH slower at pumping the gun.

When I ran an 870 I had the same problem, and could only fix it by doing what Remington should have done decades ago - I re-timed the action bars by welding on extra metal then recutting the cam surface that actuates the shell latch. The result was a bit ugly, but it completely solved the problem. In the end I got rid of the gun, but still have the modified pump handle. If you want it, send me your address and I will drop it in the mail for you... I have no use for it any longer.

I've been looking at the shell latch geometry and timing and started to think about modifications - but if this guy has already figured it all out it sure would be nice! Here's to hoping -

Bruce Allen
January 26, 2015, 22:32
Matt, check this website out:

http://www.remingtonsociety.com/forums/viewtopic.php?f=7&t=873

They are discussing your problem exactly.

kotengu
January 26, 2015, 23:21
Yep - that's the guy that's sending me the modified part. Shipped out today, so I should know shortly. Probably not before my shotgun match this weekend though. I'll make due with the 6rd tube and 7rd spring, which seems to malfunction less than the others.

Beckman
January 27, 2015, 17:48
I just brought this back up so you could say "I told you so". Several others mentioned inertia, but i just couldn't figure how there could be so much inertia the shells would stay out until the action was all the way cycled (when the primary latch lets go). Bringing the secondary latch into the equation makes perfect sense.

Now the hard question - WTF to do about it? And why doesn't it happen to everyone?

What's the feeding mechanism on a Benelli Supernova? That seems to be the latest favorite in the pump shotgun games - but from what I've read it's mostly because it's easy to load.Thanks for mentioning it. Of course, I merely proposed one theory as to what was happening. It was your photography that confirmed it, for both of us.

It sounds as though the person you quoted from another forum knows quite a bit about it, and his solution sounds very interesting. If I understand correctly, he's altered the timing by modifying part #28 on the chart. I hope that fixes your problem, and if so, it would be great if you could post photos of the modified part, as well as its dimensions in comparison to an unmodified part.

I find it amusing that the gentleman also stated, "And the folks who claim not to have a problem are often MUCH slower at pumping the gun." I know about that issue, having had others imply that I was doing something wrong when I cycled.

kotengu
January 31, 2015, 14:42
I would just like to state publicly and for the record, that "StealthyBlagga" from the Brian Enos forums is a friggin' genius. His mod fixed my issue completely, and even allowed me to use a weaker mag spring which helps me load more easily.

Here's the mod:

http://i1374.photobucket.com/albums/ag409/Stealthy_2/Rem%20870%20Action%20Bar%20Modification%202_zpsd7j laz1i.jpg

And here's the proof:

<iframe width="560" height="315" src="https://www.youtube.com/embed/MXx9HP-TdMc" frameborder="0" allowfullscreen></iframe>

Beckman
February 02, 2015, 02:21
Thanks for posting photos of the modified part, and congrats on successfully tacking down the problem and finding the one person in the galaxy who had what appears to be the correct solution.

emcroy
February 02, 2015, 04:45
My old ass issue Scattergun Tech. 870 has never given me such problems! If I want to play games and go faster, my benelli M2 has not failed! to the fuckstick that posted the pump faster, I beg to differ!

kotengu
February 02, 2015, 10:34
Follow-up: I had a 5-stage shotgun only match yesterday with plenty of birdshot and slugs. The old girl ran like a stallion finally set free. It was awesome, and I'm declaring this issue completely fixed!

Now if I can just fix the nut behind the trigger...

Bruce Allen
February 02, 2015, 21:11
You got me curious with the posted pics above and what my slide measured out to be.

I notice your original slide measures to what looks like 8.8mm

The large notch on mine measured to 8.3mm.

With the mag extension mine can hold 7 rounds.

I might have to round up my 6'6" son and get him to go with me and see if we can induce a Fail to feed.

SAFN49
February 02, 2015, 21:46
My old ass issue Scattergun Tech. 870 has never given me such problems! If I want to play games and go faster, my benelli M2 has not failed! to the fuckstick that posted the pump faster, I beg to differ!

<iframe width="640" height="360" src="https://www.youtube.com/embed/aO-DkeMTpjM?feature=player_detailpage" frameborder="0" allowfullscreen></iframe>

kotengu
February 03, 2015, 07:36
Get an Ithaca with no disconnector, much faster.

An Ithaca was my first shotgun. It was fun to put a sidesaddle on BOTH sides since it both loaded and ejected from the bottom. However - there is a danger of an OOB discharge without a disconnector, and it is physically impossible to aim with even moderate precision when your shot is activated by slamming the forend backward.

Each of the shots with the 870 are aimed and distinct trigger pulls.

SAFN49
February 03, 2015, 16:00
However - there is a danger of an OOB discharge without a disconnector, and it is physically impossible to aim with even moderate precision when your shot is activated by slamming the forend backward.
.

It would have to be seriously mistimed to have an OOB. The slide release works just like a safety sear in the FAL. Bolt locking>bolt carrier trips slide release>hammer is released striking firing pin.

homelandprotector
February 05, 2015, 20:22
A good paint job might help..... :wink:

http://i773.photobucket.com/albums/yy12/rz401/5f0a8849cddf99a60431108102a7ec1b_zps22db43fa.jpg (http://s773.photobucket.com/user/rz401/media/5f0a8849cddf99a60431108102a7ec1b_zps22db43fa.jpg.h tml)

kotengu
February 05, 2015, 23:19
I don't normally like painted rifles - but that is pretty dang cool!

SAFN49
February 06, 2015, 00:25
The shark teeth on the fore end make it faster. :wink:

ismith
February 10, 2015, 15:56
I reassembled mine with the follower backwards once, gave me all kinds of ftf issues until I figured it out.

johndoe
February 11, 2015, 01:16
The shark teeth on the fore end make it faster. :wink:
It's true!!! Thats scince!:rofl:

kotengu
February 15, 2015, 21:40
Got all the modified parts Gunkoted and reassembled, and used the function test and zeroing as a chance to play with my new camera some more - works great!

<iframe width="560" height="315" src="https://www.youtube.com/embed/let_4XMhVdM" frameborder="0" allowfullscreen></iframe>

Bruce Allen
February 16, 2015, 00:44
ya know what this means, don't ya?

No more excuses!! :biggrin:

kotengu
February 16, 2015, 10:12
No more excuses!! :biggrin:

As always, my biggest limitation is my self. :bow:

http://25.media.tumblr.com/bfdd2654d85c525bb4f97a3b63fb8560/tumblr_mxkpcff7s41ramf1yo1_500.jpg

Bruce Allen
February 16, 2015, 17:58
<iframe width="640" height="360" src="https://www.youtube.com/embed/PNA7DcVppEs?feature=player_detailpage" frameborder="0" allowfullscreen></iframe>

I have forgotten how to properly post a video.. but the song is good!!

thanks SAFN49

SAFN49
February 16, 2015, 23:13
https://www.youtube.com/watch?v=PNA7DcVppEs&feature=player_embedded


I have forgotten how to properly post a video.. but the song is good!!

Right click in the video and select copy embed code. Then paste to the files.

Bruce Allen
March 18, 2015, 23:12
..I might have to round up my 6'6" son and get him to go with me and see if we can induce a Fail to feed.

My son and I finally got together today and did a little shooting both with my 870 - that holds 8 rounds, and 1100 - that holds 7 rounds.

Found out several interesting things.

I timed Matt's shooting from his posted video's and both times he was consistently at 3.4 seconds for 10 rounds, without a "fire" command.

We fired two "warm up" runs then two or three "for time" runs, depending on how we did.

With my 870 fully loaded with 8 rounds and from a "Fire" command the best time we could get was 3.1 seconds, and had that time two times in a row.

With the 1100 fully loaded with 7 rounds the best time was 1.1 seconds from the Fire command. Had that time 2 times in a row also.

We both ran thru and my son consistently out performed me speed wise.
My best time with the 1100 was 1.4 seconds, again two times in a row.

I am sure starting from command slowed the overall timing down some.

However, there were no malfunctions such as Matt was experiencing with either shotgun.

With the 870 it just might be Matt's cycling is simply faster than we could reproduce.
It sure is close, though.

With the 1100 it really sounded like full auto.


I was reminded why I switched from the 870 to the 1100 for Combat Shooting originally: It is simply much faster to shoot.

kotengu
March 19, 2015, 06:29
Imteresting test - thanks for sharing!

Pozidriv
June 16, 2016, 12:37
I want to thank kotengu for documenting his problems and the solution so well. I guess I should thank StealthyBlagga too.

I have a Remington 870 that I have been using in 3 gun competitions for years. I use a long Choate mag extension. About a year or two ago it started giving me problems exactly like kotengu described above.

The problems were slowly happening more frequently, and I could not figure out exactly what was going on (before I found this thread). I spent a LOT of time trying to figure it out. People were trying to tell me I was short stroking it, and I knew I wasn't. But I was cycling the action very quickly, and now realize that caused "shell surge" failure to feed malfunctions.

I found this thread and a light bulb went off in my head. I realized the action bar modification described above would probably work for me too.

Unfortunately, I cannot weld. So my problem was finding someone that could do the work. After some online searching and phone calls, I found a small and new company that does custom gun work.

The company is Gun Metal Inc. (located in Millersville, Maryland): http://www.gunmetalusa.com (http://www.gunmetalusa.com/)

I spoke directly with the owner Michael Semenuk, described the problem, and emailed him kotengu's picture of the original and modified tube assembly/action bars. Having the ruler in the picture was a great idea kotengu.

Michael said this would be an easy project for his company. I was a little skeptical, but we talked some more and I gave him the part (the fore-end tube assembly with action bars).

I told Michael that it needed to be a quality job from a functional and reliable perspective because this is a competition gun. So his work had to hold up to heavy use. But, I did not care about how the modified part looked cosmetically.

When I got it back from him, I was very impressed. They did the work quickly, the quality of the work was very high, and the price was fair.

Gun Metal Inc. did such a good job modifying the part that it looks like it came that way originally from the Remington factory. Gun Metal even machined the new beveled edge on the action bar to perfectly match the angle of the other beveled edge (originally done at the Remington factory).

I'm not sure what they did to finish it cosmetically, but it matched the Remington factory bluing perfectly too. I have already shot it and the finish seems to be wearing well, and not any differently than the areas on the tube assembly/action bars where Gun Metal Inc. did not work on it.

I shot the gun in a 3 gun match last weekend (using lots of birdshot and slugs) and it worked perfectly. I am extremely happy with it.

I just registered for this forum because I wanted to provide some information on who can do this modification for anyone else looking to have this work done. I'm sure there are many other 870 shooters who have this problem. Obviously it's always better to go to someone who has done it before, and I can certainly vouch for Gun Metal Inc. now.

At some point this summer, I am probably going to send Gun Metal 1 or 2 more tube assemblies/actions bars so I have backup parts or parts for other 870s.

* I have no business or personal relationship with Gun Metal Inc. (or anyone there). I am just a happy customer. I actually did not know they existed until I contacted them about this project (very recently). I also did not get anything to post any of this information. I paid for this work (and will pay for future work) just like anyone else would.

Pozidriv

kotengu
June 16, 2016, 12:41
This is great news - thanks for sharing! I just did another one for a friend, but I would much rather just reference them to a company willing to do the work.

Do you mind if I share this on the Brian Enos forum too? There have been a few folks over there wishing they could find a company willing to do this mod.

Pozidriv
June 16, 2016, 12:49
This is great news - thanks for sharing! I just did another one for a friend, but I would much rather just reference them to a company willing to do the work.

kotengu, did you ever post anything about this problem on brianenos.com? I looked, but didn't see anything there. I am a long time member there (under a different screen name).

I thought it would be helpful if I posted this information there too (where other competition shooters would see it).

Pozidriv

kotengu
June 16, 2016, 13:39
kotengu, did you ever post anything about this problem on brianenos.com? I looked, but didn't see anything there. I am a long time member there (under a different screen name).

I thought it would be helpful if I posted this information there too (where other competition shooters would see it).

Pozidriv

Yep - I am "Matt in TN" over there: http://www.brianenos.com/forums/index.php?showtopic=203384&page=2

kotengu
June 16, 2016, 13:40
Here's another thread where it came up, and the guy was wishing someone would do this mod: http://www.brianenos.com/forums/index.php?showtopic=228706&view=&hl=&fromsearch=1

Pozidriv
June 16, 2016, 17:02
Thanks kotengu. I just posted in both threads.

I think you might be responsible for Remington 870s making a comeback!

Pozidriv

kotengu
June 16, 2016, 17:39
I think you might be responsible for Remington 870s making a comeback!


I hope so - I love my 870's! Thanks again for finding someone willing to do it professionally. That'll help more folks than me posting "look what I did, but you can't do it too".

abbynormal
June 20, 2016, 20:17
I had the exact same problem. Replaced both Shell latches (from Rem) and staked them and never had the problem since.