Remington 870P action bar lock issue

[BobM]

A couple weeks ago I bought a traded in 870P. It cycles dummies fine. However, during live fire the action bar lock sometimes rides up over the left action bar. My armorer manual is buried in storage and this is a malfunction I’ve not seen before. It blocks the shell from fully exiting the magazine. I’ve searched the net with little success. I don’t think it’s bent out of position. It might be possible that the left action bar might be forcing it out. I have three other 870s so later I’ll compare parts and maybe swap some around at the range.

[Paul Blackburn]

Let us Know what you discover.

[DDTSGM]

I'm trying to envision that in my head.

Does the action bar lock go up and down under spring pressure when the action is cocked and closed? If not the action bar lock spring may be broken. There are some pictures of what to look for in this thread:

https://pistol-forum.com/showthread....ently-unlocked

These are pictures I took with the bolt and carrier removed from one of my project 870's - the first is the normal interaction between the action bar lock and end the action bar. ETA: DON"T KBOW WHY THERE ARE TWO PHOTOS



The first photo is also instructive because it illustrates one of the important reasons for the push pull technique. You should readily see that a shooter pulling back on the forearm when firing the shotgun will create pressure which prevents the shotgun from unlocking. Pushing forward one the forearm would, of course, release this pressure and allow hammer spring plunger to push the action bar lock out of the way.

The next photo show what I imagine you have described, the action bar lock over the action bar. Despite various manipulations - twisting the forearm while cycling, cycling at different speeds, I was unable to replicate the malfunction without manipulating the action bar lock with a screwdriver as depicted in the next photo.



I don't know if you have disassembled the shotgun, removing the barrel, action bars, bolt carrier and bolt. Hopefully if you disassemble and reassemble the problem might be rectified if my next thought is relevant:

When mortaring the shotgun to remove a stuck case or cycle through a double feed, it is vital that the action bar lock be depressed. If it isn't, mortaring hard enough may cause the action bar lock to be forced over the action bar. If that is the case, disassembly and reassembly might fix the problem, although it seems to me the action bar lock springshould move the action bar lock out of the way and back into proper position - unless the action bar lock is bent.

Sorry, I'm not trying this with my shotgun.

Let us know what you figure out, I'm perplexed.

[BobM]

I stripped it on the range last night. It fired several rounds properly then started malfunctioning again. It only does it during live fire which puzzles me.

@Dan Lehr , your photo does depict what is happening. I’ll check the spring more closely but I thought it had some reasonable tension on it.

[Dave J]

Is the forend tube nut fully tightened? I’m thinking that perhaps it’s starting to work loose, which would make the action bars come further rearward than needed, and maybe causing the override issue with the lock you’re seeing.

[BobM]

Is the forend tube nut fully tightened? I’m thinking that perhaps it’s starting to work loose, which would make the action bars come further rearward than needed, and maybe causing the override issue with the lock you’re seeing.

Thanks, I didn’t think of that, I’ll check.

[BobM]

Is the forend tube nut fully tightened? I’m thinking that perhaps it’s starting to work loose, which would make the action bars come further rearward than needed, and maybe causing the override issue with the lock you’re seeing.

Well that wasn’t it. I didn’t tighten it about a turn or so. Next week I’ll swap parts around from other 870s and see what happens