Siamese Mauser actions have all the prerequisites for accommodating rimmed cartridges, including slant magazines. The 8X52 Siamese cartridge has an overall length of 2.96" versus 3.05" for the .303, so the magazine might have to be altered or handloads adjusted to fit. The actions have been successfully used in connection with .303 British, .348 Winchester and .45-70 Government ammunition.