I recently won a Weatherby Sa-459 at a banquet. It's the obsession/pistol grip version. Everything I've seen says it is Invector/Win choke threaded. Well, I just happen to have a Jebs .555 Invector/win choke that I was shooting in my Winchester 1300. The issue I am having is, I tried to screw the Jebs in tonight and it will not thread. I can take the factory choke out of the Weatherby and it threads just fine into the Winchester. Anyone have any issue why I'm having the issue that I am?