Brian,
How well do you know your 8 bore? I have 2 one is .835 the other .878 and a friend has one at .850. Obviously the ammo is not interchangable. The bullets have to be sized for the bore and the interior of the cases have to be able to accept the bullet. What case length does your 8 need? A good source for you would be Roland Hueber. His e-mail address is rh8borerifle@excite.com. He has many 8 bore components in stock bullets, wads and everything. If you had all the right components together and your bullets were sized correctly you could throw some loads together without a press. Good luck, the 8s are alot of fun!