Winchester Super-X Super Speed Rimfire Ammunition is a variation of the standard Winchester Super-X ammunition, with one option being a .22 LR 37-grain hollow point bullet. This particular option has a muzzle velocity of 1,330 feet per second due to the 135 foot- pounds of muzzle energy. There is sure functioning due to the special design and the lubricated bullet. The ammunition also provides excellent accuracy and is perfect for precision target shooting as well as hunting small game or plinking.