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Common uses: Varmint, Small Game
| Type | rifle (centerfire) |
| Typical load | 20gr reference load |
| Muzzle velocity | 4000 fps |
| Muzzle energy | 711 ft-lb |
| Published G1 ballistic coefficient | 0.185 |
| Case length | 35.56 mm |
| Overall length | 44.96 mm |
| Range (yd) | Velocity (fps) | Energy (ft-lb) | Drop (in) |
|---|---|---|---|
| 0 | 4000 | 710 | -1.5 |
| 100 | 3369 | 504 | 0 |
| 200 | 2823 | 354 | -1.6 |
| 300 | 2340 | 243 | -7.6 |
| 400 | 1905 | 161 | -20.1 |
| 500 | 1529 | 104 | -42.4 |
Small-game/varmint context — the deer- and elk-sized energy references aren't applicable to the cartridge's listed uses. When a downrange table is available, its retained-energy column can provide context; verify the exact load and follow local game regulations for legal methods.
This reference load is not verified factory-load data; confirm the displayed inputs against a reliable published source where available, and verify modeled results with your own rifle.
The .17 Mach IV is a compact, mild-recoiling .17-caliber varmint cartridge prized for flat trajectory, minimal report, and negligible kick, making it easy to spot your own hits and shoot all day. It excels on prairie dogs, ground squirrels, foxes, and similar small pests at short-to-moderate range, where its explosive tiny bullets do their work without tearing up more pelt or meat than necessary. As a wildcat it requires custom or rechambered barrels, hand-formed brass, and careful handloading, so it never reached mainstream distribution. Its small-capacity case burns modest powder charges and runs cool on barrels compared with the overbore .17 Remington, though the light bullets shed velocity quickly and are easily deflected by wind, limiting practical reach. It remains a favorite of enthusiasts who value efficiency and low blast over raw velocity, and it laid the groundwork for the later factory .17 Remington Fireball.
The .17 Mach IV is a wildcat cartridge created by Nevada gunsmith Vern O'Brien in the early 1960s, formed by necking the .221 Remington Fireball case down to accept .172-inch bullets. It was built as a small, efficient varmint round, and its name reflects the marketing claim that light bullets left the muzzle near 4,000 fps, roughly Mach IV. Though it never displaced the faster, larger .17 Remington, it earned a devoted following among varmint shooters and reloaders, and Remington eventually validated the concept with its factory-produced .17 Remington Fireball in 2007.
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