Lance, we're just customers as yourself not buds employees but try working the pump when you remove the barrel. I have a Mossberg 500 where the barrel won't come off unless I rack the pump forend down towards the stock. To put the barrel back on it has to be up. I'd also recommend lubing the barrel really well once you get it off. If none of that works I'd recommend contacting Mossberg at (203) 230-5300 | 8AM-4:30PM or use this link to message them. Sorry you're having issues but hope this helps and link to message Mossberg here............. mossberg.com/contact-us

Lance, I have a Heavy Barreled 590-A1 that I remember being tight but it did not need nothing but a twist to remove. I would contact Mossberg Customer Service to see if this is normal or not at Tel: (203) 230-5300 | 8AM-4:30PM EST or by online inquiry here : mossberg.com/contact-us

I would contact Mossberg customer service for advice and support. You can contact Mossberg customer service HERE ( mossberg.com/contact-us ) I hope this helps!