Similar to Model 27, with a sliding button on right side of receiver that permitted gun to be opened while a cartridge was in the chamber. Offered with a round (1913) or octagonal 24" barrel. The .25 rimfire cartridge was added in 1913 to those already available. Introduced in 1910 and manufactured until 1932. NOTE: Deduct 20 percent chambered for .25 rimfire.