870 problems with chambering rounds

[GetAwayDriva]

My shotgun is not chambering rounds properly. When I work the action, it is like the lifter is not lifting the new round high enough to feed it into the chamber. The round is hitting on the bottom of the chamber. I slide the action back and the lifter lifts up properly and then I can chamber the round. Any ideas of what to look at? I need help ASAP as I have a match coming up next weekend and it would be nice if my shotgun ran.

[Boxerglocker]

How old is the 870? How many rounds? Are the action bars properly lubed and broken in, are binding at all? Have you reworked the trigger/carrier group recently?

When all appears lost to explaination. I findf that a good detail strip, clean lube and reassemble usually resolves issue. A good clean and light relube of your trigger /carrier group will probably fix it.

Edited May 5, 2016 by Boxerglocker

[Dan Sierpina]

Kind of like short stroking? Did you make any changes at all recently?

[ShootfastRunfaster]

Make sure that your lifter is not bent and hanging up on the recesses inside the receiver. Remove your bolt and attempt to push the lifter up and down while the trigger plate is still in place. It should move freely without touching the sides of the receiver. If it is making contact on a side, you can use a flat blade screwdriver and make minor adjustments to it to center it. The first recesses that it can come into contact with are the shell latches, and the second set is the action bar tracks.

If the lifter moves freely, check your carrier dog spring. It is the coil spring under the silver plunger that puts tension on the carrier dog. A weakened or shortened spring will not supply enough tension to the carrier dog and lifter engagement will be weak. That will cause the lifter to not raise up high enough to align the shell. I tried shortening one in an attempt to make loading easier, but it backfired and a low lifter was the result.

Kuan

[GetAwayDriva]

Thanks so much for the replies! The gun is actually really clean, that was the first thing we looked at. It isn't a short stroking problem. Haven't made any changes to the trigger group. We just put a new barrel on it a short while ago and hadn't really shot it much after that. Turns out the chamber area of the new barrel does not have the same radius that the old barrel had. It actually has no radius at all. So we put a radius on it. It also seems that the lifter is rubbing on a shell latch. So made some adjustments there. Carrier dog spring seems to have enough tension on it. Will be taking it out to the range tomorrow to see how it runs.

Thank you Kuan and Dan (see you guys in about a week for Heman) and Boxerglocker!