.17 Winchester Super Magnum (WSM)
.17 Winchester Super Magnum, is a rimfire rifle cartridge developed by the ammunition company Winchester in 2012. It descended from the .27 caliber nail-gun blank by necking down the blank case to take a .17 caliber (4.5 mm) bullet. Initial loadings were with a 20-grain bullet, delivering muzzle velocities around 3,000 ft/s. Winchester, in conjunction with Savage, introduced this cartridge at the 2013 SHOT Show.
The brass case for this round is roughly 50% thicker than the 17 HMR, and the max average internal pressure is 33,000 psi, compared to the 17 HMR's 26,000 psi. Factory ammunition is available from Winchester, Federal, American Eagle, and more recently, Hornady.
Hornady 17 Win Super Mag and Federal Ammunition American Eagle 17 Win. Super Magnum cartridges are currently only available with 20-grain polymer-tipped projectiles rated at 3,000 FPS at the muzzle.
Several options from Winchester are available, including Varmint HV 17 Winchester Super Magnum with a 20-grain polymer-tipped projectile rated at 3,000 FPS, Varmint HE 17 Winchester Super Magnum with a 25-grain polymer-tipped projectile rated at 2,600 fps, and Varmint-X 17 Winchester Super Magnum which is available with a lead-free 15-grain polymer tipped projectile, rated at 3,300 FPS.