.17 Winchester Super Magnum

.17 Winchester Super Magnum, commonly known as the .17 WSM, is a rimfire rifle cartridge developed by the ammunition company Winchester in 2012. It descended from a .27 caliber nail-gun blank cartridge by necking down the blank case to take a .17 caliber (4.5mm) bullet. Initial loadings were with a 20 gr bullet, delivering muzzle velocities around 3,000 ft/s.

Development
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. The 17 WSM is not compatible with firearms chambered in 17 HMR and vice versa as the two cartridges have different dimensions.

Factory ammunition
Factory ammunition is available from Winchester, Federal, American Eagle. Federal Ammunition American Eagle 17 Win. Super Magnum cartridges are currently only available with 1.3 gram (20 grain) polymer-tipped projectiles rated at 914 m/s (3,000 fps) at the muzzle.

Several options from Winchester are available, including Varmint HV 17 Winchester Super Magnum with a 1.3 gram (20 grain) polymer-tipped projectile rated at 914 m/s (3,000 fps), Varmint HE 17 Winchester Super Magnum with a 1.6 gram (25 grain) polymer-tipped projectile rated at 793 m/s (2,600 fps), and Varmint-X 17 Winchester Super Magnum which is available with a lead-free 1 gram (15 grain) polymer tipped projectile, rated at 1,006 m/s (3,300 fps).

Firearms
Currently, rifles firing the 17 WSM are the Savage B-Mag bolt action, heavy barrel B-mag target edition. Ruger Model 77/17, Winchester 1885 Low Wall single shot, and the semi-automatic Franklin Armory F-17. The F-17 is the first gas-piston operated rimfire firearm designed to handle the higher pressures of this cartridge. Also recently Jard Inc. joined this list with their J71 17 WSM AR 15 rifle.