Mossberg 590 Shockwave Issue, Trigger Won’t Always Pull

Good evening.
Having a problem I’m hoping some if you gunsmith types may be able to help with. I recently purchased a Mossberg 590 Shockwave. Cool gun, but it’s prone to malfunctioning due to a trigger issue. Shooting Winchester 2 3/4”, 7 1/2 shot heavy loads (only load I’ve tried), the trigger hangs up about every third shot. And by hanging up, I mean it can’t be pulled even a little bit. No movement at all, so it’s not like the safety is engaged where you can still get a little bit of movement. BUT... if I release pressure on the trigger and pull it again it will fire. Crazy, I know, but that’s what it does. This has been the case on two separate range trips, one before cleaning the gun and one after a thorough disassembly/cleaning. I’m unable to replicate this by dry-firing, it’s only when firing live rounds. I contacted Mossberg and was told to blow out the trigger mechanism with canned air and also to try another type of ammo, and if that didn't fix it then the gun would have to be sent in for inspection/repair. In the meantime, I thought I’d see what help I might find here, or if anyone here has ever heard of such a thing.
Will mention that I have a Model 500 that I’ve owned for over 20 years and have never had an issue of any kind with.
Thanks!

1KPerDay said:

After you take a close look at the trigger group look at the safety detent ball and spring. They generally want to stay on due to the direction of recoil but something might be loose.

first thing though is swap trigger groups with your 500 and see if the problem goes with the trigger group.

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Hadn’t thought about swapping trigger groups. That would surely narrow down the problem. Thanks!

entropy said:

It has a disconnector in it. It is not resetting for whatever reason, most likely caused by the way you are holding it. Your trigger finger is not going forward enough to reset it.

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Okay, this time I was able to replicate the problem by dry-firing it without fully resetting the trigger. Although this is something I’ve never, ever done with a proper shoulder-mounted shotgun, it’s entirely possible that I was doing exactly that with the Shockwave’s funky bird’s-head grip and with my deathgrip hold on the gun. A trip to the range will tell for sure.
Thanks very much, entropy!

Okay, final report: Operator error all the way. Turns out I was gripping that “bird’s-head” grip too far down, which had my finger stretched out & keeping tension on the trigger, preventing it from resetting consistently. Confirmed by comparing my hand position when shouldering my 500. I feel pretty sheepish, but maybe this will help somebody else. Thanks, y’all!