Mossberg was prompt in sending a prepaid shipping label and I shipped it to them. There was a bit of a delay in me getting it boxed up, finding time to arrange pickup, etc.
Mosssberg did acknowledge receipt the next business day after it arrived, so I don't have any concerns about customer service. They did say it could be about 6-8 weeks, so, hopefully, I will know more by the end of the month.
Mossberg put a new barrel assembly on it and shipped it back, and I received it today. Only a three week turnaround at their factory, so I don't have any complaints there at all.
They noted the original had a bad gas cylinder. The shipping label indicates they put 8 rounds of buck, 8 rounds of 2 3/4 field loads and 14 rounds of 3 inch field loads through.
I'll test it hopefully soon. The issue that I was having was manually cycling a loaded round, but I will check that at the shooting range. No issue with cycling an aluminum a-zoom snap cap, but it didn't have that problem before, either.
I hope it runs well-- my point in posting all the above was not to bad mouth it. It did seem like an odd issue.
I took the 940 out today with the replacement barrel, and it manually cycled/press checked rounds just fine.
With the original barrel I needed to smack the charging handle to get it unloaded or press check. Preferably with a mallet, as my hand was sore for about two weeks afterwards. Now it is easy.
I ran 56 rounds through. No issues with the below ammo. The lightweight 1145 fps estate stuff (not pictured) didn't want to cycle, but that's not an issue.