Raimey,
No, I meant .516" head diameter. The largest diameter you measured was .525", and the chamber must be larger than the cartridge. You can't fit a .544" 450 head cartridge into a .525" hole. When I say "head diameter", don't get it confused with rim diameter( for MB base rim is .585", but .595" fits most rim recesses).
fuhrmann,
MB cartridges were available in calibers larger than 11.15, and longer than 60mm.
Mike
Mike,
I am not convinced.
The .525 diameter was taken 1/4'' or ca 6 mm below the base - quite the same as on my .450 Express cartridge. Not easy to measure exactly due to the conical shape. But real base diameter definitely will be even larger, possibly oversize for a MB cartridge.
fuhrmann
