870 Broken or Short Stroking.

[M4Fundi]

I have an amazing 1983 Rem 870 PM with a 20" bbl. Excellent condition and the most accurate slugger I have ever seen. Problem. When shooting it I often eject a hull clean, but it does not pickup the next shell and the next shell is firmly inside the magtube. It has the stock extra-heavy mag tube spring.

So, is it possible to eject a hull clean and short stroke the gun? I don't think so... if anything I'd think the shell would at least leave the mag tube and jam up the gun, since the shell is left in the mag tube I'm thinking its a mechanical issue... experience or ideas with this?

[26 Inf]

1983 Rem 870 Police Magnum with Stock Spring - do you mean original mag tube spring? If so that would be the first thing I'd check, especially if it is an extended magazine PM.

When it skips picking up the next shell is it generally the last shell in the tube? What may be happening is that that shell is behaving like a crash test dummy and rebounding from the recoil as you cycle - exacerbated by a weak spring.

Simplest, easiest, cheapest answer.

ETA: if you are certain your spring is good - I wouldn't be unless it is new - then next time it happens, stop before you cycle the action on the empty chamber click, roll the shotgun over, loading port up, and check which shell latch is holding the shell in the tube - the one on the left, on the one on the right as you look into the loading port from the stock end of the shotgun.

[Joe Mamma]

1983 Rem 870 Police Magnum with Stock Spring - do you mean original mag tube spring? If so that would be the first thing I'd check, especially if it is an extended magazine PM.

When it skips picking up the next shell is it generally the last shell in the tube? What may be happening is that that shell is behaving like a crash test dummy and rebounding from the recoil as you cycle - exacerbated by a weak spring.

Simplest, easiest, cheapest answer.

ETA: if you are certain your spring is good - I wouldn't be unless it is new - then next time it happens, stop before you cycle the action on the empty chamber click, roll the shotgun over, loading port up, and check which shell latch is holding the shell in the tube - the one on the left, on the one on the right as you look into the loading port from the stock end of the shotgun.

26 Inf raises some great points. It's a concept called shell surge. It seems to be more common now with competition shooters who try to shoot quickly and have lots of rounds (i.e, weight) which the magazine spring must work against during recoil. It can also be caused by and/or made worse by a weak magazine spring.

If you are motivated, you could have it modified like this below:

Joe Mamma

[M4Fundi]

Guys as always appreciate the time to give me the info... I train on Tuesdays and will check these things. FYI tho, it is usually the 2 or 3 shell that I get a click, empty chamber and shells still in the tube. Normally I associate a short stroke to with a malfunction or weak ejection, but the videos show strong ejection and then click.

I guess I think the spring is good based on how darn hard it is to reload fast from the very hard spring tension I am pushing shells against (not very scientific way of testing the spring) so I will run these tests and some others I was recommended to do on Tues and get back to y'all.

The shotgun is suppose to go to Nighthawk this week and I wanted to know what was up before sending it.

Forgot to ask:

26Inf -Difference between the right/left shell latch?

Joe M- explain the mod there please?

[Joe Mamma]

Joe M- explain the mod there please?

M4Fundi, I am far from an expert on 870 shotguns. However, I have shot them a lot and had the same or similar problems as you are experiencing.

I have also used a modified fore-end tube assembly identical to the one pictured (but that's not my picture), and it solved those problems. To make the modified part pictured, someone needs to weld some extra material onto the factory part. I used a company called Gun Metal Inc ( www.gunmetalusa.com ). I have no ties to them.

My memory may be a little off. But my understanding is that when pumping the shotgun, the unfired shotgun shell is released from the magazine tube in 2 stages. The first stage is a very small movement of the loaded shotgun shell. The second stage is the big movement where the shell is pushed back onto the carrier (the flap that lifts the shell right before it is chambered).

The modification changes the timing or the first stage. So it makes the second stage more reliable. I think it will make the first stage happen sooner, so it gives the shell more time to be in the proper position for the second stage.

Someone feel free to add to this or correct me if I am wrong.

Joe Mamma