The cartridge is not based on the 303, but they have the same or similar head diameter, as does the 30-40 Krag. The 405 case may work better, due to length, but the 303 and 30-40 will work fine(may have to adjust rim dia.), if necessary, you can load the bullets "out" to the correct oal. With regard to cast bullets, I prefer .002" over groove dia. With regard to using 444 cases, the head diameter is too large, .468" vs .454", plus, it is simi-rimmed, not rimmed, and the extractor may or may not hold it. BTW, a .373 expander seems about right for a .375" bullet, you may have to bell the case a little for cast bullets.
Mike
Last edited by Der Ami; 07/16/17 06:41 PM.
