My 870P - pull trigger, no bang - slide permanently unlocked

[Chris17404]

Hi, all.

Yesterday afternoon I brought my 870 Police (HD gun) to the range for a little practice. The first 10 or so shells went fine. Then the next 3 or 4 I had intermittent failures to fire. After that, it stopped firing at all. It appears that the slide is permanently unlocked. Loading a shell or not, and sending the forend forward does not lock the action. When pulling the trigger the hammer does not fall. And I noticed that it appears the slide release lever in the front of the trigger guard is stuck up (in the pressed position). I have not had time to disassemble the gun yet, but I wanted to check with the experts here first to see if you had any suggestions on diagnosis steps and resolution. Thanks for your time.

Chris

[Chris17404]

OK, I disassembled the action, and found this. It appears that the action bar lock and action bar are not interfacing correctly when the action is closed. It remains in the unlocked state. This picture is from an old post on another site but it seems to illustrate the issue perfectly. Mine looks like the 2nd (unlocked) picture.

When I removed the trigger group, the hammer fell as it should when the trigger is pressed. I did notice, though, that when resetting the trigger, the disconnector did not have "two stages". Meaning, while the trigger is still pressed, the disconnector did not catch the hammer when pressed fully back. It's like the sear caught it. I would think that's a problem as well. Is there a two-stage hammer catch like that when the hammer is resetting on an 870?

Any ideas on how to resolve this?

Top to bottom: action locked, action unlocked, action open

http://rem870.com/forum/download/file.php?id=617

[DDTSGM]

One of the reasons for your problem may be a broken action bar lock spring.

Taken your trigger plate/firing mechanism out of the receiver and make sure the spring is not broken. The end of the spring is indicated by the arrow. The action bar lock should go up and down under spring pressure.

105412

Replacing od the spring hasn't been taught in factory armorer schools for over a decade, maybe two. A legit gunsmith should be able to do it, but it may be cheaper to buy a new trigger plate.

Let us know if this isn't the problem.

[Chris17404]

Hi, Dan. Thank you for the suggestion. Luckily, that was not the root cause.

I have successfully resolved the issue. It was the action bars that were not going fully forward to allow the lock to engage. So I assumed it had to be somehow related to the barrel/forend interaction. (FYI I have a Magpul forend.) I was right. I tried loosening the magazine cap a few clicks (allowing the barrel to move a bit further forward when action is closed) and noticed immediately that the action as able to fully lock closed and the trigger/hammer/unlocking worked correctly. So I again disassembled the barrel/forend and noticed that the "castle nut" that secures the forend to the action bars was quite loose! It must have rotated several times with use and allowed the forend to impede the full movement of the action forward. Once I re-tightened that castle nut down appropriately, the gun functioned normally.

Lesson learned: Periodically inspect that all screws are tight on my 870!

Chris

[Erick Gelhaus]

Hi, Dan. Thank you for the suggestion. Luckily, that was not the root cause.

I have successfully resolved the issue. ... So I again disassembled the barrel/forend and noticed that the "castle nut" that secures the forend to the action bars was quite loose! ...

Lesson learned: Periodically inspect that all screws are tight on my 870!

Glad you found it.

[gato naranja]

So I again disassembled the barrel/forend and noticed that the "castle nut" that secures the forend to the action bars was quite loose! It must have rotated several times with use and allowed the forend to impede the full movement of the action forward. Once I re-tightened that castle nut down appropriately, the gun functioned normally.

Lesson learned: Periodically inspect that all screws are tight on my 870!s

Glad you got that sorted out.

I have not had a fore-end tube nut loosen on me (yet). On the other hand, I have wanted to throw than one complete fore-end assembly out the window when said nut refused to back off during a detail strip.

[Chuck Whitlock]

Some clear nail polish on the threads should help eliminate that.

[Chris17404]

Some clear nail polish on the threads should help eliminate that.

Good idea. Thank you.