Ruger 77/17 Rotary .17 WSM 6-Round Magazine, Matte Black Md: 90521 The Ruger 77/17 Rotary Magazine is a standard factory replacement magazine. This magazine is for 77/17 models and similar variants chambered in .17 WSM and holds 6 rounds of ammunition. It is made of polymer and features a matte black finish. This magazine is made to Ruger's specifications and tolerances, using the same manufacturing and materials as the original equipment magazines, ensuring perfect fit and operation.