The .17 WSM (Winchester Super Magnum) is a high-velocity rimfire cartridge introduced in 2013, the fastest production rimfire round. Firing a tiny bullet at exceptional speed, it offers a very flat trajectory for precise varmint and pest-control shooting at extended rimfire ranges.

The .17 WSM was introduced by Winchester in 2013 and is notable for being the fastest production rimfire cartridge, achieving velocities beyond other rimfire rounds. It was developed from an industrial component case rather than a traditional cartridge case, an unusual origin that allowed it to push a tiny .17-caliber bullet faster than established rimfire magnums like the .17 HMR. Ballistically the .17 WSM fires a very light bullet — commonly around 20 to 25 grains — at high velocity for a rimfire, producing an exceptionally flat trajectory and extended effective range with minimal recoil. That flatness and reach make it a standout for precise varmint, predator, and pest-control shooting at distances beyond what slower rimfire cartridges comfortably reach. Its tradeoffs follow the rimfire pattern: it is best suited to small targets, the ammunition is more expensive than common rimfire rounds and cannot be reloaded, and its availability is narrower than the ubiquitous 22 LR and .17 HMR. It is a specialized precision rimfire rather than a high-volume plinking round. Today the .17 WSM is used for varmint and predator hunting, pest control, and target shooting, with steady if specialized availability. Its combination of class-leading rimfire velocity, a very flat trajectory, and minimal recoil is why it occupies the high-performance end of the rimfire category.

General information about this caliber — not a recommendation for this specific firearm.