.17 Mach IV
The.17 Mach IV / 4.4x35mm is a wildcat centerfire rifle cartridge, based on the.221 Remington Fireball case, necked down to fire a 0.172 in bullet. The cartridge was introduced in 1962 by Vern O'Brien. The cartridge offered an easy case conversion and good ballistics, but could not compete against the.17 Remington.
.17 Mach IV
ps500 · Self-photographed · CC BY 3.0
- Name
- .17 Mach IV
- Field
- wildcat cartridge · rifle cartridge
- Region
- United States
VALÉORINE Encyclopedia
VALÉORINE documentary reading
Documentary summary
The.17 Mach IV / 4.4x35mm is a wildcat centerfire rifle cartridge, based on the.221 Remington Fireball case, necked down to fire a 0.172 in bullet. The cartridge was introduced in 1962 by Vern O'Brien. The cartridge offered an easy case conversion and good ballistics, but could not compete against the.17 Remington.
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Documentary evidence
Documentary basis
Authority files
wikidata · Q4545173 · wikipedia · .17 Mach IV
In this article
Overview
Overview
The name, Mach IV, comes from the claim that the bullets can reach 4000 ft/s. Due to the relatively small case capacity, even small variations in powder of 0.5 gr can lead to the difference between a safe and dangerously over pressure load. Aftermarket barrels for the XP-100 pistol were sometimes marked ".17 Mach III" due to the lower velocity produced by the shorter barrel. The.17 Mach IV became very popular with varmint hunters, so much so that in 2007, Remington introduced its own very similar version, the.17 Remington Fireball.
Key facts
Key facts
• Name —.17 Mach IV • Origin — United States • Type — Rifle • Designer — Vern O Brien • Design Date — 1962 • Parent —.221 Remington Fireball • Case Type — rimless bottlenecked • Bullet —.172 • Neck —.206 • Shoulder —.361 • Base —.378 • Rim Dia —.378 • Rim Thick —.045 • Case Length — 1.400 • Length — 1.830 • Rifling — 1 in • Primer — Small Rifle • Bw2 — 25 • Btype2 — HP • Vel2 — 3680 • En2 — 797 • Bw3 — 25 • Btype3 — HP • Vel3 — 3890 • En3 — 849 • Balsrc — 6mmBR Hodgdon
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- United States
Named but not plotted · 1
17 Mach IV is associated with United States.
Country
Primary material
Documents and archives
reference work
- “.17 Mach IV”, English Wikipedia, consulted as further reading
Reputable secondary · Wikipedia
authority record
- Wikidata, structured authority record Q4545173:.17 Mach IV
General reference · Wikidata
Notes from the source article
Cited by Wikipedia
Notes from the source article
These works are cited by the source article, in its own numbering. They are recorded as its citations, not as sources VALÉORINE has verified.
- 1.17 Caliber Wildcats. www.6mmbr.com.
- 2.Hodgdon Online Reloading Data.
- 3.Barnes, Frank C., Cartridges of the World, 7th Edition, p171
- 4.Jim Saubier. Which .17?. www.saubier.com.
- 5.Wildcat Cartridges: .17 Mach IV Column by Layne Simpson in Handloader Magazine
References
Citations
References
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reference work
Secondary witnessauthority record
General reference
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Connections
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Broader subject
2- rifle cartridgeTerminology
Established from a fact already recorded on a verified source.
- wildcat cartridgeTerminology
Established from a fact already recorded on a verified source.
Further particulars
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Further particulars
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Within the Encyclopedia.17 Mach IV is connected to 2 other published records in the VALÉORINE Encyclopedia.
The Encyclopedia exists whether or not anything is for sale. Corrections are recorded rather than overwritten, and every version of this record is kept. Published 17 August 2026.
Elsewhere in Militaria
6,095 published records in this field, each with its sources named.
- .17 Bumble BeeTerminology
- .17 HM2Terminology
- .17 HMRTerminology
- .17 HornetTerminology
- .17 PMC/AguilaTerminology
- .17 Remington FireballTerminology
- .17 RimfireTerminology
- .17 Winchester Super MagnumTerminology
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