Hi folks - while putzin with a White BG series Thunder. I am trying to find what Choke tube would fit this BP shotgun.

It appears to have a Hasting .665 in now but I feel it does not screw in properly as I can still see threads when looking down the barrel. The throat needs to be longer to cover those threads and blend in to the chamfer.
While by far I an no expert I sure wouldn't want to shoot this thing with exposed threads.

I have other similar choke tubes some longer but I don't want to force them. I have tried a brass brush on a drill to scrub the threads. I am going to a gun smith tomorrow to hopefully get those threads clean. I am sure they are dirty.

So anybody have a White BG series Thunder with an extended turkey choke? It was the only choke I got with the gun. The tube will bottom 'out' on the barrel but it feels like it is only biting a portion of the threads in the barrel and like I said I can still see threads.

Thanks for any help
JW