The .17 Mach IV is a wildcat

Wildcat cartridge

A wildcat cartridge, or wildcat, is a custom cartridge for which ammunition and firearms are not mass produced. These cartridges are often created in order to optimize a certain performance characteristic of an existing commercial cartridge.Developing and using wildcat cartridges does not...

 centerfire rifle

Rifle

A rifle is a firearm designed to be fired from the shoulder, with a barrel that has a helical groove or pattern of grooves cut into the barrel walls. The raised areas of the rifling are called "lands," which make contact with the projectile , imparting spin around an axis corresponding to the...

 cartridge

Cartridge (firearms)

A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...

, based on the .221 Remington Fireball

.221 Remington Fireball

The .221 Remington Fireball was created by Remington Arms Company in 1963 for use in their single-shot bolt-action pistol called the XP-100. This was a special round designed for an experimental pistol, and has the highest velocity of any commercial pistol cartridge.-History:In the early 1960s...

 case, necked down to fire a .172 bullet. The cartridge was introduced in 1962 by Vern O’Brien it offered an easy case conversion and good ballistics but could not compete against the .17 Remington

.17 Remington

The .17 Remington was introduced in 1971 by Remington Arms Company for their model 700 rifles.It is based on the .223 Remington, necked down to .172in , with the shoulder moved back. It was designed exclusively as a varmint round, though it is suitable for smaller predators. There are those such as...

.

The name Mach IV comes from the claim that bullets can reach 4000 ft/s

Feet per second

The foot per second is a unit of both speed and velocity . It expresses the distance in feet traveled or displaced, divided by the time in seconds...

, despite this being only about Mach 3.5. Due to in case capacity, even small variations in powder of 0.5 gr can lead to a difference of 100 ft/s (30.5 m/s).

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

.17 Remington Fireball

The .17 Remington Fireball was created in 2007 by Remington Arms Company as a response to the popular wildcat round, the .17 Mach IV. Factory loads drive a 20 grain bullet around 4,000 ft/s . Velocity is close to the .17 Remington but with significantly less powder, and therefore less heat and...

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See also

• .17 Remington Fireball
  .17 Remington Fireball
  The .17 Remington Fireball was created in 2007 by Remington Arms Company as a response to the popular wildcat round, the .17 Mach IV. Factory loads drive a 20 grain bullet around 4,000 ft/s . Velocity is close to the .17 Remington but with significantly less powder, and therefore less heat and...
  
  
• .221 Fireball
• 4 mm caliber
  4 mm caliber
  This article lists firearm cartridges which have a bullet in the .172 in / 4.5mm caliber range.*Length refers to the cartridge case length.*OAL refers to the overall length of the cartridge.All measurements are in mm .-Rimfire cartridges:...
  
  
• List of rifle cartridges