Velocity classes
Standard-velocity, high-velocity, and subsonic are load descriptions. Their numerical limits and test conditions belong to the exact product. A rifle catalog velocity should not be assumed for a handgun.
THE CARTRIDGE LIBRARY · RIMFIRE
.17 WSM
Winchester Super Magnum is a separate .17-caliber rimfire with a larger case than .17 HMR. Its designation describes the cartridge family, rather than a metric equivalent of HMR.
2A Ledger reference desk · Sources checked October 18, 2026
Read the dimensions
- Overall · min–max
- 1.440–1.590 in
36.576–40.386 mm - Case length · max
- 1.200 in
30.480 mm - Bullet maximum
- 0.1725 in
4.382 mm - Rim diameter · max
- 0.333 in
8.458 mm
Know the exact name
At a glance
- Cartridge family
- Rimfire
- Bullet specification
- 0.1725 in / 4.382 mmBullet maximum
- Factory examples
- 1 loadsSelected, sourced examples below
- Weight in cited examples
- 25 grGrains measure mass, not powder charge
.17 WSM is identified by its complete cartridge designation. The resource-table alternative is 17 Winchester Super Magnum. A caliber number, bullet diameter, or family resemblance on its own does not identify ammunition compatibility.
Do not confuse .17 WSM with .17 HMR or with the unrelated centerfire WSM rifle family.
Dimensions: open the exact dimensional drawing ↗. The displayed number is bullet maximum, rather than an assertion that every manufactured projectile or barrel has this exact diameter.
Origins & evolution
Background & development
Winchester introduced the .17 Winchester Super Magnum in 2013. Its unusual starting point was an industrial rimfire case used in powder-actuated tools, rather than a necked-down .22 WMR case. Contemporary reporting described Winchester drawing on the stronger .27-caliber tool-blank case to develop a sporting rimfire with a larger performance envelope.
The launch emphasized a 20-grain load advertised at 3,000 feet per second, an ambitious figure for a commercial rimfire. The new case required firearms designed for the WSM; sharing a .17-caliber bullet with the successful HMR did not make it the same cartridge. Savage’s B.MAG was closely associated with the early introduction. Historically, the WSM represents a different route to a faster rimfire: Winchester revisited the case itself, using experience from its industrial-ammunition business instead of simply changing the bullet in an established sporting case.
Historical sources: Winchester: company innovation timeline, 2013 ↗ · American Rifleman: contemporary WSM development report ↗
Construction changes the story
Loads, variations & specialty offerings
Bullet design
Round-nose, hollow-point, and polymer-tipped bullets have different intended roles. A tip or hollow cavity is not a reliable substitute for the maker’s product description.
Specialty products
Target and reduced-noise products may trade velocity or bullet shape for a particular use. Verify reliable operation and the firearm maker’s ammunition restrictions rather than assuming every rimfire product behaves alike.
In the cited .17 WSM examples, bullet weights are 25 grains. These are the weights actually present in this source selection, not a claim that every possible loading is listed.
Bullet construction background: Hornady: anatomy of a bullet ↗. Exact product descriptions and velocities are cited in the factory table.
From the factory catalog
25 grains
2,600 fps
Jacketed hollow point
Compare all 1 cited factory load records
| Maker / product | Bullet mass | Published construction | Muzzle velocity | Test barrel | Source |
|---|---|---|---|---|---|
| WinchesterX17W25 | 25 gr 1.62 g | Jacketed hollow point | 2,600 fps 792 m/s | Not stated here; see source | Winchester · PDF p. 2 ↗ |
Explore the published data
Ballistics you can inspect
What can be plotted reliably?
The sources checked for this guide do not provide a comparable barrel-length series. A single factory muzzle-velocity specification does not establish a velocity curve. The factory records and any missing test conditions are identified below.
An estimate needs an anchor and a defensible method. No curve has been invented from bullet diameter or from another cartridge’s name.
How to interpret the comparison
Changing bullet weight also often changes bullet design and propellant choice. Two curves are comparisons of the listed products, not a controlled experiment proving that bullet weight alone caused the difference. Catalog downrange points are projections under the maker’s conditions; barrel-study points are recorded observations in the study firearm.
Direct answers
Common questions
What is .17 WSM?
Winchester Super Magnum is a separate .17-caliber rimfire with a larger case than .17 HMR. Its designation describes the cartridge family, rather than a metric equivalent of HMR.
What diameter does .17 WSM use?
The cited dimensional standard lists 0.1725 inches (4.382 mm), bullet maximum. This drawing convention is different from a casual caliber nickname.
Are similarly named cartridges interchangeable?
Do not confuse .17 WSM with .17 HMR or with the unrelated centerfire WSM rifle family.
Are the graph values measured or estimated?
This guide has no supported multi-point graph in the sources reviewed. Its factory specifications and source links are shown in the load section.
Does higher energy mean the best load?
Energy is calculated from mass and velocity. It does not establish accuracy, expansion, penetration, pattern density, recoil, or suitability for a particular firearm. Use the exact product documentation and firearm manual.
Trace the facts
Sources & methodology
Skives & petals: read the jacket construction →
Compiled by 2A Ledger from the linked standards, manufacturer publications, and identified test records. Checked October 18, 2026. Historical tests and older catalogs retain their original dates; a listing here does not establish current availability.
- SAAMI: dimensional drawing · PDF p. 17 ↗
- Winchester: historical timeline ↗
- Winchester · PDF p. 2 ↗
- Winchester: company innovation timeline, 2013 ↗
- American Rifleman: contemporary WSM development report ↗
Diameter figures preserve the cited drawing convention. Inch–millimeter conversion uses exactly 25.4 mm per inch. Factory specifications describe the maker’s test setup; your firearm, ammunition lot, temperature, and measuring method can produce different results. This is an educational factory-ammunition reference, not a reloading manual.