The AO-27 is a semi automatic, gas-operated 10x54mmR flechette rifle and AK derivative. The automatic device of a design of Shiryaev of joint-stock company-27 under оперенную подкалиберную bullet Дворянинова is tested in ВНИИточмаш. Tests have shown very good настильность подкалиберных оперенных bullets, but кучность, a little bit conceding to a usual shooting ammunition. Use of similar cartridges in the automatic weapon allowed to increase a resource of a trunk twice.