The 6mm AR is a
centerfire
Two rounds of .357 Magnum, a centerfire cartridge; notice the circular primer in the center
A centerfire cartridge is a firearm metallic cartridge whose primer is located at the center of the base of its casing (i.e. "case head"). Unlike rim ...
wildcat cartridge
A wildcat cartridge, often shortened to wildcat, is a custom cartridge for which ammunition and/or firearms are not mass-produced. These cartridges are often created in order to optimize a certain performance characteristic (such as the power, si ...
initially designed by Robert Whitley for long-range performance in an
AR-15
An AR-15-style rifle is any lightweight semi-automatic rifle based on the Colt AR-15 design. The original ArmaLite AR-15 is a scaled-down derivative of Eugene Stoner's ArmaLite AR-10 design. The then Fairchild Engine and Airplane Corporatio ...
rifle
A rifle is a long-barreled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves ( rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with ...
.
Description
The cartridge uses a
6.5 Grendel
The 6.5mm Grendel is an intermediate cartridge jointly designed by British-American armorer Bill Alexander, competitive shooter Arne Brennan (of Houston, Texas) and Lapua ballistician Janne Pohjoispää, as a low-recoil, high-precision rifle cart ...
case that has been
necked-down to accept a 6.2 mm (.243 in) bullet.
The 6mm AR takes advantage of the wide variety of 6.2 mm (.243 in) caliber bullets. Slim, long bullets with high ballistic coefficient are ideal for energy retention at long ranges.
It is similar to the
6PDK which also uses a 6.2 mm bullet and a similar
muzzle energy
Muzzle energy is the kinetic energy of a bullet as it is expelled from the muzzle of a firearm. Without consideration of factors such as aerodynamics and gravity for the sake of comparison, muzzle energy is used as a rough indication of the de ...
and case capacity to the 6mm AR and 6.5 Grendel, in a casing somewhat popular for the AR-15, a necked-down
6.8mm Remington SPC
The 6.8mm Remington Special Purpose Cartridge (6.8 SPC, 6.8 SPC II or 6.8×43mm) is a rimless bottlenecked intermediate rifle cartridge that was developed by Remington Arms in collaboration with members of the U.S. Army Marksmanship Unit and U ...
casing.
6mm AR Turbo 40 Improved
This variant uses an
Ackley Improved
Parker Otto Ackley (May 25, 1903, Granville, New York – August 23, 1989) was an American gunsmith, barrel maker, author, columnist, and wildcat cartridge developer. The Ackley Improved family of wildcat cartridges are designed to be easily made ...
fire formed case with less tapering and a 40-degree higher shoulder permitting a larger powder capacity. It is claimed by its maker to be capable of driving a or heavier grain projectile at (satisfying the "
6mm Optimum
The "6mm Optimum" is a concept popularized in 1999 by military writer Stanley C. Crist.
History
Crist argued for the adoption of a 6mm service rifle chambering as a replacement for the venerable 5.56×45mm NATO and 7.62×51mm NATO, calculatin ...
").
6mm Rat and FatRat
These wildcats also push forward the shoulder of the same necked Grendel case similar to the Turbo 40, yielding more powder capacity. or heavier grain VLD boat-tail bullets have to be seated deeply within the case neck, however, rendering some of these volume gains illusory but there is an increase in volume even with the longer bullets nonetheless.
6mm Grinch
Similar to the 6mm Turbo 40 and 6mm FatRat, the 6mm Grinch has a blown-forward shoulder on par with the
6mm Dasher to eke maximum powder capacity from the necked Grendel case. In 2016, Greg King won a
National Bench Rest Shooters Association event with a "Grinch" wildcat, besting a field of mainly
6mm PPC competitors.
[http://forum.accurateshooter.com/threads/6mm-grinch-defeats-entire-field-of-6ppcs.3912901/ 6MM GRINCH Defeats entire Field of 6PPCs]
See also
*
6mm ARC
The 6mm Advanced Rifle Cartridge (6×38mm), or 6mm ARC for short, is a 6 mm (.243) caliber intermediate rifle cartridge introduced by Hornady in 2020, as a low-recoil, high-accuracy long-range cartridge, designed for use in the AR-15 platform a ...
*
6mm Optimum
The "6mm Optimum" is a concept popularized in 1999 by military writer Stanley C. Crist.
History
Crist argued for the adoption of a 6mm service rifle chambering as a replacement for the venerable 5.56×45mm NATO and 7.62×51mm NATO, calculatin ...
*
.223 Remington
The .223 Remington (designated as the 223 Remington by the SAAMI and 223 Rem by the CIP) is a rimless, bottlenecked rifle cartridge. It was developed in 1957 by Remington Arms and Fairchild Industries for the U.S. Continental Army Command ...
*
List of rifle cartridges
List of rifle cartridges, by primer type, calibre and name.
File:Cartridge Sample 2.jpg, 350px, From left to right: 1 .17 HM2,2 .17 HMR, 2.5 .17 wsm, 3 .22LR, 4 .22 WMR, 5 .17/23 SMc, 6 5mm/35 SMc, 7 .22 Hornet, 8 .223 Remington, 9 .223 WSSM ...
*
Glossary of firearms terminology
The following are terms related to firearms and ammunition topics.
A
*Accurize, accurizing: The process of altering a stock firearm to improve its accuracy.
* Action: The physical mechanism that manipulates cartridges and/or seals the breech. ...
References
Pistol and rifle cartridges
Wildcat cartridges
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