The GP100 is a group of double-action revolver. It was manufactured by Ruger and has been in production since 1985. The Ruger GP100 features a 6-shot design and all-steel construction. It comes in .357 Magnum and .38 Special versions. Both models can fire .38 special rounds, .38 special +P and .38 Special +P+.

Barrel lengths of the Ruger GP100 range from 3″, 4″ and 6″ with partial or full length underlugs. Finishes are done either in blued steel or stainless steel. Owners of this gun have the assurance that safety has been thought of during the production of this weapon. The firing pin is mounted in frame and the transfer bar must be between the hammer and firing pin for the cartridge to be fired.