The 303-25 is the only way to go, I have a mate who had both a 25 and 270 on the 303 case. The 25 was a very popular pig gun in its time. There were many wilcats made I still have load listings for the 22/303 sprinter, 22/303 Swift, 22/303 Falcon, 243/303, 25/303, 270/303 and standard 303 British
I only have standard millitary 303's just to collect.
Aussie Dog
