870 Express Magnum Fail to Feed

[olcoot]

A friend brought it to me to see if I can figure out what’s wrong. Before starting on it I thought I might get some ideas. Shooting 3 ½ mag shells most of the time, Winchester Supreme. The gun is virtually new, and very tight action. The problem has existed since the first time he fired it.

When the gun is cycled without firing, shell from mag drops immediately into the space below the bolt, on top of the ‘feed lever’ that pushes it up into line with the breech after the bolt moves to the rear. This is as it should be, far as I can tell. Cycling without firing works just fine. Snap an empty chamber and cycle a shell from the mag works just fine.

He says that when you fire a shell, the ‘feed lever’ flips up before the slide cycles, throwing the feeding shell under it to hang up. Not every time, but often enough to make it unreliable. I have tried cycling the action, but haven’t fired it yet.

I’m much less familiar with the 870 (beyond basic field strip) than with the Winchesters I use. Any suggestions where to start?

 

[dfariswheel]

The first suspect, especially in the 3 1/2" Super Magnum is that the shooter is "short stroking" the slide.

This is easy for a shooter new to pump guns in general and especially in the longer stroke 3 1/2" guns, even more especially if they try to operate the action too fast.
Essentially what happens is that the shooter just fails to pull the slide all the way to the rear either because he's unused to the pump, or he's trying to operate it fast and fumbles it.

There is a chance a new gun could have a problem, but the 870 action is not known for any kind of "mis-timing" that would allow this to happen.

I'd test fire the gun and make SURE the action is being pulled fully to the rear before trying to close it.
If the gun is actually defective, either take it back where he bought it, or contact Remington for instructions on how to ship it in for repair.

 

[olcoot]

Yeh. Weather here has delayed my trying it out, but I shot it with standard shells this afternoon, with no problem. On a hunch from past experience, I tore it apart and thoroughly scrubbed the entire action, including the chamber. (though this gun is a couple of years old, he hardly shoots it, but he's thoroughly familiar with pumps).

When I scrubbed it out, a layer of something peeled off the inside of the action; probably some thick packing lube. Had to take brushes and solvent and really scrub to get it out. (unfortunately, the solvent has also begun to remove the camo paint from the receiver...oh, well...) I suspect this was gumming up the timing mechanism and causing the problem.

Haven't got it back together, and will have to wait till tomorrow to test fire, but the thorough cleaning and light lubing may well solve the problem.