Hi
I've been lurking around here for quite some time. You guys have have an incredible amount of knowledge packed in here, and I'm hoping to tap into some of it.
I've decided to switch gears and take a big step back in time. I've reloaded a wide range of modern cartridges over the years, but recently I've started retooling to cast my own bullets and load black powder cartridges (both of which I've never done before) out of my new Uberti El Patron ('73 SAA clone) .45 colt and Uberti/Cimarron 1866 lever rifle in .44-40. This forum has been a big help, but I'm still a bit foggy on what diameter I should be shooting for when it comes to my SAA.
I acquired a Saeco 2-cavity 230 gr mould that is listed as being .454 diameter. Not my first choice of bullet, but I like the potential versatility it may give me if I ever decide to run cast bullets out of my 1911, and more importantly, it was one of the only few .45 pistol bullet moulds currently available in these nutso times we're in.
I slugged and caliper'ed my cylinder's chamber throats and they all run very near .454. I slugged the bore twice and it measured .450 on the money both times. Is that .004" difference quite a bit? I understand a throat smaller than groove diameter is a bad deal, so at least this one doesn't fit that bill. But .004 over seems like a lot. I'm not sure what my bullets will cast to with my new stash of 20:1 alloy, but I'm hoping I can shoot them as-cast rather than sizing them.
Assuming my mould throws a .454 bullet, is jumping thru a forcing cone down to a .450 bore too harsh of a transition? Should I consider sizing down closer to to groove diameter? If so, how many thousandths under throat diameter can I go down before I start getting blow-by, if any, in my throats upon firing?
Or... is that .004" difference not enough to worry about, and as long as I find out my bullets cast out anywhere between those two marks, just load up and make smoke?
Thanks for you input. I think I'm going to like this new-to-me side of the shooting addiction, er, I mean sports.