Supermag Timing Issues

General discussion about Remington 870 shotgun.
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Gobspur
Newbie
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Joined: Sun Jan 20, 2019 9:34 pm

Supermag Timing Issues

Post by Gobspur » Sun Jan 20, 2019 9:55 pm

Hello, I have an 870 supermag turkey gun that I am having issues with. Gun was bought new in 2013. I have only shot 3.5 inch loads and it has done this on several occasions.

After a shot when I pump the gun, it will allow a shell to come out of the magazine to soon, which comes up and jams with the spent shell before it can be extracted. After doings this a couple of times, I thought maybe I was short stroking it, but I have simulated it by putting a spent shell in the chamber, and a live round in the magazine, and purposely pumped it hard. Same thing happens. It does it whether I pump it slow, medium, or fast.

The spent shells do not appear to be catching in the chamber, and they extract fine when there are no shells in the magazine. I have also had it apart and cleaned everything. Why is it allowing shells out of the magazine and up the lifter before the spent shell is extracted?
Thanks

Mb1500
Shotgunner
Posts: 17
Joined: Fri Aug 04, 2017 3:21 am

Re: Supermag Timing Issues

Post by Mb1500 » Thu Feb 07, 2019 5:11 am

Haven’t had my 870 out in a long time, been even longer since I owned a super mag.

The two shell latches on the inside of the receiver (tabs that can be depressed, must be pushed during disassembly) are what controls the shells. If my memory serves me correct the first one disengages when the pump initially starts moving rearward and then the shell is now held with the second latch. This is released when the pump reaches the rear most position and the shell shoots into place.

This is what happens when people short chuck it. Second latch is not depressed and shell is not released. If your shell is interfering with the shell trying to be ejected I would look at that latch to see if it is failing and allowing the shell to escape the magazine tube before the pump is fully rearward. If you work the action slow you should be able to see and feel what’s going on.

Mb1500
Shotgunner
Posts: 17
Joined: Fri Aug 04, 2017 3:21 am

Re: Supermag Timing Issues

Post by Mb1500 » Fri Feb 08, 2019 1:35 pm

Just pulled out the 870, disregard the previous statement. When you load a shell into the mag tube with the fore arm fully extended it sits on the primary shell latch. If you flip the gun upside down from a shooting position this latch is on the right hand side. This latch controls the shell until the pump travels all the way back, it then releases the shell. Any additional shells are held by the secondary latch, which only holds them until the pump reaches 75% of its forward travel and then the new shell is held by the primary latch ready to be fed into the action.

Chilly
Experienced Shotgunner
Posts: 69
Joined: Thu Jan 31, 2019 12:49 am

Re: Supermag Timing Issues

Post by Chilly » Sun Feb 10, 2019 1:36 pm

OP, have you figured this out yet?

My thoughts on primary and secondary latches: if there was just one latch I suspect one could let the slide dwell in one spot allowing entire magazine of shells to attempt to park themselves on top of the follower instead of just one shell. Having two latches lets the action bars play traffic cop. Sequence of operations:

1. Shell in magazine is held by the port latch.

2. When slide is near fully aft the port action bar releases a shell from the mag tube and jumps onto the carrier. Less obvious is that the next shell on deck moves rearward in the tube and is held by the starboard latch.

3. Around the same time the spent shell rim strikes the ejector on the port wall of the receiver, flipping the hull out of the gun.

4. As slide is moved forward the carrier lifts the front of the shell up toward the chamber and the starboard latch releases the shell onto the port latch.

5. Slide moves fully into battery.

I dont think you have a feeding malfunction, I think you have a failure-to-eject malfunction. Is your spring ejector still there? When shucking out an empty hull with no rounds in magazine does your empty hull sail free of the ejection port with vigor and zeal? Does it dribble out lazily? Does it not eject at all? I'm not concerned for why the fresh shell arrived early (I suspect its on schedule), I'm wondering why the spent hull is still loitering in the receiver.

I have wingmasters so my knowledge of supermags is limited.

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