Re: Siamese Mauser in 303 British project finished...sorta.
Standard .303IMP is a great round. It's even better (better bullets) if chambered up on a .308 barrel. I note that a normal round duplicates it, like a .308 or 7.5x55 - but - it's a .303 IMP or perhaps a .30/303IMP and that is what makes it yours.