I just became the owner of a free set of dies they say Redding 6PPC Competition bushing neck size die #58319 in what appears to be in excellent shape. The box contains two calibrated head dies. 1 size die, and 1 seater die. I am contemplating getting a 6PPC bolt gun. I am a novice for sure. I haven't the faintest idea how they work? When they say bushing die, does that mean I can get another bushing in say 6BR? Thanks Lou