Why does the forearm on my Mossberg 590 pump shotgun lock up sometimes and prevent hull from ejecting?

[Sam7sf]

Op, by chance are you putting grease on your parts? I remember helping a guy trouble shoot a 590a1. These guns like to be ran dry.

 

[Younggun]

I like Mossberg shotguns, but I’ve seen several that like to grip cheaper aluminum based shotgun hulls. Seems the base doesn’t spring back like the more expensive brass based hulls.

Doesn’t sound anything like a user error or short stroke issue to me. Short stroking really wouldn’t have anything to do with a hull sticking after being fired.


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[DougC]

Thanks all for the suggestions. I am using Winchester Super Target and Federal Field and Tgt loads; #8 shot. During match there is usually 30-40 minutes between shooting so the gun cools off. Its possible the gun lube is wearing off during match so I will try adding lube in-between stages. It is not practical to drop a cleaning rod down barrel as I am actively engaged in the stage match and that would be a lot of time and safety issue on the range. I just have to muscle the forearm to rear to get the shell to eject and suffer extra time.

BTW: I am reaching out to this forum after this reply from Mossberg Customer service. I quote

"Thank you for your email. Based on your serial number the shotgun you have is 22 years old. Unfortunately, this is a very odd thing due to the fact it does it briefly and then works fine again. Especially with it being cleaned regularly."

Thanks for help and advice from others. I think taking it to a gunsmith is next.

 

[EZ-E]

Try tightening the bars to the pump action. I had a Winchester that had ejection issues & that solved the problem.

 

[DougC]

Try tightening the bars to the pump action. I had a Winchester that had ejection issues & that solved the problem.

What are the bars?

 

[EZ-E]

What are the bars?

The pump action bars...

 

[DougC]

The pump action bars...

View attachment 299768

 

[DougC]

OK, and how is that done. They don't appear to be something fixed by shooter.

 

[EZ-E]

OK, and how is that done. They don't appear to be something fixed by shooter.

Here's a video of full break down on a 590 Check if the bars are worn or bent where they make contact with the bolt. Or take it to a gunsmith to have them check it out.

 

[DougC]

Here's a video of full break down on a 590 Check if the bars are worn or bent where they make contact with the bolt. Or take it to a gunsmith to have them check it out.

Good choice of video as it best one I have found with lighting to see how to take one apart and reassemble. I will look at the forearms and other points of contact of wear and tear.