Superformance ammunition is loaded with proprietary propellants that increase the velocity ratings up to 200 feet per second compared to other popular brands.
Product Info for Winchester SUPER-X RIFLE .30-30 Winchester 150 grain Jacketed Hollow Point Brass Cased Centerfire Rifle Ammunition Winchester Super-X Centerfire Rifle Ammunition is just as accurate as any other Winchester ammo offering incredible reliability. It also is able to supply rapid and controlled expansion and the ability to travel at high velocities.