Sorry, hope you didn't pay much for it. As above, it's a British .38/200 service revolver with a chopped barrel and probably re-bored chambers to accept .38 Special cartridges. The grips on it may be worth more than the revolver itself. These things were imported by the boatload in the 1950s-1960s and sold cheap by direct mail. Yours is too early to be a Lend-Lease, as those didn't start until around late 1941. Your SN (if without a SV prefix) will date it as shipping about June 1941. A Lend-Lease revolver will have "UNITED STATES PROPERTY" stamped on the topstrap.