I dont have a modified case for the Rigby so it was trial and error getting this to drop into the chamber of my #1. This was the final seating depth when it would finally drop in. I was really hoping it would have a longer throat. That is a 400gr TSX and I would like it seated out about another 1/4" it would look cooler and it would give me a lot more powder capacity. For now I am going to see what I can get out of it as is then go from there.