All About the 6mm ARC — Performance, Specs, Video Reviews

By Editor

In June 2020, Hornady introduced the 6mm ARC, a new SAAMI cartridge optimized for AR-platform rifles*. The new 6mm ARC is basically a 6.5 Grendel necked down to 6mm, with the shoulder moved back around .030″. That pushed-back shoulder does reduce case capacity (and velocity), but we assume Hornady did that to create a shorter, proprietary chamber so people could not simply neck-down Lapua 6.5 Grendel brass, as has been done for years with Robert Whitley’s outstanding 6mm AR wildcat.
CLICK Image for official SAAMI Specifications:

If you are intrigued by the 6mm ARC, you’ll find the products you need at Brownells — barrels, bolts, mags and even complete 6mm ARC Rifles. Midsouth has 6mm ARC ammo and reloading dies. For general information, see 6mm ARC Wikipedia Info Page.

What Is the 6mm ARC Cartridge?
The 6mm ARC cartridge is a new SAAMI-spec cartridge based on the 6.5 Grendel case necked down for 6mm bullets, with the shoulder moved back 0.030. Yes it is designed to run in AR15-platform rifles. You’ll need a new barrel, bolt, and mags. If you already have an AR chambered in 6.5 Grendel, the ONLY thing you need to change is the barrel. Everything else — bolt, magazines, gas

Source: Accurate Shooter