I have seen a Lancaster DR / with sidelocks and single trigger, in caliber 444Marlin. The rifle was built about 1910 in caliber 370? and sometime in the sixties the caliber was changed for 444 Marlin.
It seems like the caliber change was made in England, it is nitro proofed.

Is there anyone that knows or have seen anything similar before? I'ts a very nice gun, but the caliber seems litle bit strange for English DR.

Sven