This is Super Thumb's only rifle magazine loader other than rifles that use pistol magazines. Because of this .22 caliber guns popularity there were a number of people who sought help with this high capacity magazines that several after-market manufacturers started making magazines for and in recent years even Ruger has taken part in producing. 2.2mm x 32.5mm a 1.65" x 1.28" Fits extended capacity Ruger 10/22 magazines