6mm ARC

6 mm Advanced Rifle Cartridge
TypeCenterfire rifle
Place of originUnited States
Production history
Parent case5.6×39 mm (.220 Russian), 6.5mm Grendel[1]
Case typeRimless, bottleneck
Bullet diameter6.18 mm (0.243 in)[2]
Neck diameter6.96 mm (0.274 in)[2]
Shoulder diameter10.924 mm (0.4301 in)[2]
Base diameter11.201 mm (0.4410 in)[2]
Rim diameter10.44mm* (0.4410 in)
Rim thickness1.5 mm (0.059 in)[3]
Case length37.85 mm (1.490 in)[2]
Overall length57.40 mm (2.260 in)[2]
Case capacity2.20 cm3 (34.0 gr H2O)[citation needed]
Rifling twist190.5 mm (1:7.50")
Primer typeSmall rifle
Maximum pressure (SAAMI)358.53 MPa (52,000 psi)[2]
Ballistic performance
Bullet mass/type Velocity Energy
6.67 g (103 gr) ELD-X Precision Hunter 853.44 m/s (2,800.0 ft/s) 2,429 J (1,792 ft⋅lbf)
6.80 g (105 gr) BTHP BLACK 838.2 m/s (2,750 ft/s) 2,388 J (1,761 ft⋅lbf)
7.00 g (108 gr) ELD Match 838.2 m/s (2,750 ft/s) 2,459 J (1,814 ft⋅lbf)
Test barrel length: 610 mm (24 in)
Source(s): [4]

The 6 mm Advanced Rifle Cartridge (6×38mm), or 6mm ARC for short, is a 6mm (.243) caliber intermediate rifle cartridge introduced by Hornady in 2020, as a low-recoil, high-accuracy long-range cartridge designed for the AR-15 platform.

The cartridge makes use of 6 mm (.243) bullets, which are known for their high ballistic coefficients due to the high sectional density with less drag and better energy retention at extended ranges. With the release in 2020, Hornady also launched three factory loads with 103, 105 and 108 gr (6.7, 6.8 and 7.0 g) bullet weights and advertised G1 ballistic coefficients of .512, .530 and .536 respectively.[5]

Compatibility with the AR-15[]

For an ordinary AR-15 rifle chambered for the .223 Rem/5.56mm NATO, a new barrel, magazine and bolt are required to convert to the 6mm ARC.[6] The 6mm ARC utilizes the same bolt head size as the 6.5mm Grendel, and 6.5mm Grendel-compatible AR-pattern box magazines have also been used successfully with the 6mm ARC.[7] The 6mm ARC therefore can also be a suitable chambering for shorter "mini-action" bolt-action rifles.[citation needed]

Several firearm manufacturers have announced that they will be offering factory rifles chambered in the 6mm ARC.[8][9]

See also[]