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940 JM Pro...slack @ barrel-chamber

ArmyAviator

Copper BB
Literally brand new out of the box 940 JM Pro. I've detached and reattached 9 shot magazine @ forearm, trying to tighten the barrel onto the action; there's slack that, i.e., R hand on grip, L hand on barrel...compress...visible and audible movement where barrel meets action.
Thoughts? This can't be normal...?
I've several other auto-loaders, none are Mossberg.
 
Can you tighten the mag tube ext and nut any more with the bolt back? Maybe wiggle barrel while you do it?

Welcome Aboard! :)
 
I have zero experience with the M940 semi shotgun. I do have 2 M930 series shotguns and I have disassembled them extensively. Reading your post I’m not entirely clear on your issue. Can you maybe take some pics or provide a more concise description of the issue?
 
I had the same issue awhile back. The magazine tube extension screws into the nut. I had screwed the tube in the nut too far which did not allow the nut to tighten down enough causing the barrel to move slightly and the forearm to rattle. Back out the tube from the nut a bit and tighten down with the nut. Then turn the extension tube down a bit more. It doesn't have to be gorilla tight.
 
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