Did you do anything special to break the gun in? Are you putting oil in the gun? Is the gas system clean?

I had a Browning Gold Stalker with a 24" barrel for a while. I found it was very finicky with shells as well. Try to shoot shells with smooth cases (not the ribbed shells like Federals, etc). Mine got to be an absolute dog when it got cold out. Wouldn't feed anything I put in it. My buddys with Golds and Super X2s finally all got tired of the same problems and sold them and got Benellis and havne't looked back.

I loved the gun in warmer weather, but I rarely shoot a shotgun when it is nice out, so mine had to go.