View Full Version : Moss 590: Safety bounces ON after vigorous pumping

July 9, 2000, 08:49 PM
Okay, I admit, I was screwing around and took it off. Now upon replacing it, the safety selector on the tang will bounce ON (safe) after a couple of racks. More accurately, I think the bolt is bumping the safety sear thingy back into the 'safe' position.

I'm not a complete idiot and have successfully undertaken _MUCH_ bigger things that safety removal/installation but apparently I'm missing something here.

Yes, the detent spring and ball were properly replaced. And it doesn't seem to matter how loose or tight the screw is (actually seems to do better when loose).

Thanks for your help!

George Stringer
July 10, 2000, 06:39 AM
Jordan, since it didn't happen before you disassembled I have to guess that you just assembled something wrong. Remove the trigger assembly and observe what happens when you work the action. You might be able to see what's happening. If not you might just need to take it to your local smith and ask him to assemble it correctly. George

July 10, 2000, 09:45 AM
I have watched the internals during pumping and it appears as though the bolt, or actually the rear of the firing pin, slightly bumps the safety sear (piece shaped like an upside down 'L'). And only then during the most forceful pumping. It looks as though it is meant to be a close space tolerance there.. hence the 'L' shape.

As to handing it to a smith: I like to consider myself fairly self-sufficient and somewhat capable. Would only farm a problem out as a VERY last resort. Haven't had to yet through much bigger problems than this.

Has anyone seen or experienced this problem with a Mossberg?

[This message has been edited by Jordan (edited July 10, 2000).]

July 10, 2000, 11:32 AM
It is possable that the dentent in the safety button itself is worn. Replace that plastic one with a steel one from Brownell's.

Artificial intelligence is no match for natural stupidity.

July 10, 2000, 12:56 PM
Grayfox: After you were kind enough to suggest an idea, I feel bad shooting it down but the reason I had it off in the first place is because I was replacing the old one with a new steel one.

No, the detent is in place and seems to feel as strong as ever... I don't know what to say for this thing--

George Stringer
July 10, 2000, 01:28 PM
Jordan, if you have the long leg of the "L" to the rear, then the safety itself is assembled correctly and the problem has to be something else. Maybe the new detent ball is slightly smaller in diameter than the old. You might try switching them back and see if it still does it. George

[This message has been edited by George Stringer (edited July 10, 2000).]

July 11, 2000, 07:47 AM
This isn't any help, but my 500 Mossberg pump does this if you pump it really hard. It only happens when I let by brother shoot it! It seldom happens to me, so I haven't checked into it yet. My father's 500 will also do this from time to time (especially when trying for doubles at the trap range!). It must be something in the design.

July 11, 2000, 04:49 PM
Thanks for your response Conan! This is good (and bad) to hear. Maybe I'm just pumping way to hard...? I wonder how this problem could be alleviated? Maybe a slight alteration to that safety block to help it clear but still fully and safely function.

I'm sure someone will reply warning me not to do try that....

July 14, 2000, 12:52 PM
I had a problem with my 590 going on safe and I sent it back to Mossberg and they said the firing pin spring was broke and they replaced it and it works fine now.As you noticed the rear of the firing pin touches the safety so I guess the firing pin could not move foward easy enough so the safety moved back.The gun would still fire but the primer indention was light.

July 14, 2000, 06:19 PM
Glock19: Thanks! This is the best idea/story I've heard yet. It's been about a week since I posted this and after trying all kinds of things it's still just as bad (or worse) as ever.
I noticed last night while looking at it that the firing pin did seem quite stiff.... I'll definately check that spring out tonight!
Thanks again!

July 16, 2000, 01:15 PM

Worn firing pin.
There is a sholder on the firing pin where the firing pin retaining pin holds. That was worn/rounded allowing the firing pin to rest too far back thus hitting the safety block.
There is an identical sholder on the other side of the firing pin so the gun is back up in action after fliping it 180... but will buy a replacement soon.

Thanks for all your suggestions.

July 16, 2000, 05:07 PM
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Worn firing pin.[/quote]

Wow. Is this an old gun (I'd guess not, since it's a 590)? Has it seen some kind of odd use (or abuse)? Do you dry fire it alot? I've never heard of this happening, but it sure is an eye-opener.

I'd be very curious about why this happened. Firing pins sometimes break, but I've never heard of one wearing like this.

July 17, 2000, 08:54 AM
Excessive dry firing is the only thing I can figure... short of a firing pin that somehow slipped past quality control (I doubt that's the case).
It's a few years old and I've dry fired it some... not enough to hurt it I wouldn't think...maybe though.