mossberg fire control problem

[Andrew Wyatt]

While my mossberg 500 was in vegas, being used to test stages, it had a fail to fire malfunction twice in which the slide was operated, the trigger was pulled, and a weak click was heard, after wich the action unlocked allowing the slide to be actuated again.

I was able to simulate the malfunction with an empty gun by retracting the bolt approximately .25 inches and then pulling the trigger. (which cocked the hammer to "half cock", and then released it, which is a problem in and of itself, since halfcock shoudn't be a position where you can do that) this leads me to believe that the hammer is "following". is this a common problem, and what could cause this to occur?

 

[Dave McC]

A worn or broken sear could do that. I'd also want to drop the bolt and check for excess grease and grunge.

 

[Bruce626]

Although only a recent owner of a Mossberg 500, I've put several thousand rounds thru it and have done diligent research on the history and performance of the gun, including all of the TFL threads that come up on a search... I'd have to say that what you've experienced is NOT a "common problem".

Your careful description does not sound like a classic "short shuck" (classic is what I call problems that I, myself, occasionaly experience).

Have you fired your shotgun enough to wear out or break your sear as Dave McC suggests as a possible cause? I ask that only because it sounds like you'd have to have fired many, many thousands of rounds to get to the "worn out" possibility and as I sort of recall from your earlier posts, your shotgun is of fairly recent vintage.

Could the screw inside the ejection port be loose? Do you have any accessory that replaced the trigger group pin with a screw of some sort (e.g., a sidesaddle or a Weaver Convert A Mount), and which if too tight could bind up the bolt? I know this is sort of like asking "Is it plugged in?", but ya nevva know.

--Bruce.

 

[Andrew Wyatt]

my mossberg has had less than 200 rounds through it, and it has no sidesaddle or scope mount on it.


It might be a one time thing. I'm going to take it out and shoot it lots next time i go shooting and see if it repeats itself.