The Mk. IV British service revolver was accepted in 1899, and was made in a variety of barrel lengths, but only one caliber: .455. It should not be confused with the smaller frame Mk. IV .38.
The Mk. IV British service revolver was accepted in 1899, and was made in a variety of barrel lengths, but only one caliber: .455. It should not be confused with the smaller frame Mk. IV .38.