Browning B-80 Problems

I have a late 80's model Browning B-80 12ga, built by Beretta using their A302 design under a different name. The gun came with two barrels, one chambered in 3" mag and one in 2 3/4". For years I only used it with the 3" barrel and buckshot, only fired it once at a deer and didn't pay much attention to the ejection.

I didn't feel like running out to get 20ga shells so I switched it over to the 2 3/4" barrel and took it dove hunting last weekend. It wouldn't cycle any dove loads, either high or low brass. Did a little homework and the gun is known to have trouble with light loads, but higher brass, a good cleaning, and a "recoil adapter" fixed the issue for most people.

I took the gun apart and cleaned it very well, the mag tube was pretty gunked up, and it already had the recoil adapter installed, so I figured I had found the issue. Here's the kicker, put it all back together and now it won't even eject 3" mag buckshot. With either barrel, it will kick a shell back to the lifter, but the receiver just doesn't come back enough to eject the spent shell and allow the new one to chamber. Yes I've cleaned the gas ports on both barrels, and they weren't dirty before. No I did not lubricate the gas cylinder, as I read it is supposed to be dry.

Getting really frustrated with this gun. If it weren't a birthday present from pow pow I would have chunked this damn thing in a lake by now. If no one has had this issue, can anyone recommend a gunsmith in the BR area who is knowledgeable with old Browning and Beretta shotguns? Between the two barrels its all the shotgun I'll ever need, but it's a glorified single shot right now. TIA