Looking to find out from what cases can one form .375 Flanged brass, I see RCBS makes a limited production case forming die, and I'd like to figure out how to form "practice brass". I don't own a gun in the cartridge yet, but I'm looking at either the .375 Flanged or the .450-400. Brass availability of the .450-400's pushing me that way, though I do believe I prefer the .375 Flanged (I already shoot .375 H&H, and cast for it, have the bullets on hand, etc). If there's an angle to form the brass, the decision's likely made. Thanks in advance for any info.