Currently shooting Nitro HTL out of my sx3 12ga. If I wanted to try tss which 3" she'll should I start out trying. I have a rhino .660 and rhino .670 as well as a Briley that came with the Longbeard Edition shotgun, not sure the constriction though. Figured if you were going to shoot tss out of a 12 gauge you really don't need a 3.5" shell as a 3" should be more than adequate