The longest I can offer is:

BPCR - the Mauser M1871 at 53" precisely (i.e. to a 1/16")

Smokeless - the Swissicon G96/11 at 51 5/8"


The Mauser M1918 anti-tank rifle was 66 1/8" long. The cartridge was 5 3/16" long. How long was the Boys?

Patrick