There was some discussion of this in the Sig Next Generation Squad Weapon, but I did not see an individual thread. I'm going to take a drink of this new Kool Aid flavor. There are a number of articles out there, but this one is a relatively quick read with some comparative 500 yard+ performance vs. the .223 and .308.
Everything You Need To Know About The 6mm ARC
Vs. 308, it has better long range ballistics, less than half the recoil, and is a 30% lighter rifle platform than a 308 AR. What's not to like? LOL I do have to hold my nose a bit as this caliber is a Hornady development and I think Steve Hornady is a jackass.
I plan to borrow the lower from one of my AR15 match rifles and will build an upper with the goal of having a long distance range toy. In the near future I'd like to take some courses at Ridgeline and after trying some 22NRL matches may step up to centerfire PRS matches. I already built an AR 6.5CM and Mrs. Mountain has a nice 308 Aero M5, so those calibers are covered. I thought about a 6CM rebarrel of my 6.5, but 6CM tends to burn through barrels more quickly and is a little hotter than I really need. I can always do that later for relatively short money but I'll probably just stick with the 6.5.
One of the logical digs against the 6 ARC is its lower velocity out of a gas gun. SAAMI specs are 2700 fps for a 108 grain projectile at 52,000 psi. I assume that's a bolt action 24" barrel. Hornady load data lists 52,000 psi as the limit for gas guns yet specs a limit of 62,000 psi for bolt guns. Like the 6.5CM AR I built, I'll use a high pressure JP bolt headspaced to my new barrel which will facilitate slightly hotter loads. Another point of attraction for me is that some of the best heavy projectile 6 ARC loads use Varget and 2520, of which both I use and keep stock in bulk. I'll use one of the better match barrel makers for a 24" (maybe a 22"?) barrel and run a rifle +2 gas system. Might take a couple months before I have my new barrel, but as I have done with prior 'builds' will post targets good or bad along the way.
I realize there are better performance options, but as far as I have seen thus far those options are all in the AR-308 platform. For the cost of a new barrel + bolt, new mags, and not much else we'll see how it goes...
Everything You Need To Know About The 6mm ARC
Vs. 308, it has better long range ballistics, less than half the recoil, and is a 30% lighter rifle platform than a 308 AR. What's not to like? LOL I do have to hold my nose a bit as this caliber is a Hornady development and I think Steve Hornady is a jackass.
I plan to borrow the lower from one of my AR15 match rifles and will build an upper with the goal of having a long distance range toy. In the near future I'd like to take some courses at Ridgeline and after trying some 22NRL matches may step up to centerfire PRS matches. I already built an AR 6.5CM and Mrs. Mountain has a nice 308 Aero M5, so those calibers are covered. I thought about a 6CM rebarrel of my 6.5, but 6CM tends to burn through barrels more quickly and is a little hotter than I really need. I can always do that later for relatively short money but I'll probably just stick with the 6.5.
One of the logical digs against the 6 ARC is its lower velocity out of a gas gun. SAAMI specs are 2700 fps for a 108 grain projectile at 52,000 psi. I assume that's a bolt action 24" barrel. Hornady load data lists 52,000 psi as the limit for gas guns yet specs a limit of 62,000 psi for bolt guns. Like the 6.5CM AR I built, I'll use a high pressure JP bolt headspaced to my new barrel which will facilitate slightly hotter loads. Another point of attraction for me is that some of the best heavy projectile 6 ARC loads use Varget and 2520, of which both I use and keep stock in bulk. I'll use one of the better match barrel makers for a 24" (maybe a 22"?) barrel and run a rifle +2 gas system. Might take a couple months before I have my new barrel, but as I have done with prior 'builds' will post targets good or bad along the way.
I realize there are better performance options, but as far as I have seen thus far those options are all in the AR-308 platform. For the cost of a new barrel + bolt, new mags, and not much else we'll see how it goes...
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