6mm AR

6mm AR
Type	Centerfire rifle
Place of origin	United States
Production history
Designer	Robert Whitley
Specifications
Parent case	6.5 Grendel
Case type	Rimless, bottleneck
Bullet diameter	.243 in (6.2 mm)
Neck diameter	.271 in (6.9 mm)
Shoulder diameter	.4323 in (10.98 mm)
Base diameter	.4433 in (11.26 mm)
Rim diameter	.4449 in (11.30 mm)
Rim thickness	.0591 in (1.50 mm)
Case length	1.525 in (38.7 mm)
Overall length	2.260 in (57.4 mm)
Case capacity	36 gr H2O (2.3 cm3)
Rifling twist	1-8"
Primer type	Small rifle
Ballistic performance
Bullet mass/type Velocity Energy 105 gr (7 g) Berger VLD 2,750 ft/s (840 m/s) 1,763 ft·lbf (2,390 J)
Source(s): http://www.6mmbr.com/gunweek068.html

The 6mm AR is a centerfire wildcat cartridge designed by Robert Whitley^[1] for long-range performance in an AR-15 rifle.

Description

The cartridge uses a 6.5 Grendel case that has been necked-down to accept a 6 mm (.243 in.) bullet.

The 6mm AR takes advantage of the wide variety of .243 in. caliber bullets. Slim, long bullets with high ballistic coefficient are ideal for energy retention at long ranges.^[2]

It is similar to the 6PDK which also uses a 6mm bullet and a similar muzzle energy and case capacity to the 6mm AR and 6.5 Grendel, in a casing popular for the AR-15, a necked-down 6.8mm Remington SPC casing which does not need special magazines to fit the AR-15.

See also

• List of rifle cartridges
• Glossary of firearms terminology
• .223 Remington

References

1. ↑ http://www.6mmbr.com/gunweek068.html
2. ↑ http://6mmar.com/6mm_AR_Loading_Info.html

Cartridges derived from the 7.62×39mm or its derivatives
First generation derivatives	5.6х39mm/.220 Russian 9×39mm .366 TKM
Second generation derivatives (based on 5.6х39mm/.220 Russian)	.22 PPC 6 mm PPC 6.5mm Grendel .30 Walker
Third generation derivatives (based on 6.5mm Grendel)	6mm AR