The round-butt 3-inch Model 13 was the specific variant issued to FBI field agents. The round-butt grip frame improved concealability in shoulder holsters and was a key FBI requirement when the Bureau chose the Model 13 as its standard sidearm. Type: Revolver Action: Double-Action Caliber: .357 Magnum Capacity: 6 Year introduced: 1974, USA Weight: 33.5 oz Overall length: 8.5" Status: Discontinued Intended use: Duty, Carry, Plainclothes