Not sure if it's "need", whims, desires, problem solving, or just a niche.
What is the ARC? Well ARC is short for Advanced Rifle Cartridge, but what is that? Just a name, it's actually a necked down version of 6.5 Grendel to 6mm. 6.5 Grendel vs the .264 LBC, just a naming difference to get around a trademark. Which is just is a way to have increased capacity vs using a 6x45 in a AR-15 length action / Magazine (noticed I included the action length statement) . Just to dummy it down, now is there a differences, sure we see shoulder diameter and or angle differences etc etc.
Honestly it's just a different dress. This is nothing to take away or detract from the 6mm ARC, I don't own one it's probably a great cartridge.
Typing this I'm remembering a conversation with a gunsmith years ago when the 6mm Creedmoor was starting out. He sought thoughts from a group which I was included on the cartridge. Two of us replied pretty much the same. What can it do that the 6mm Remington aka .244 Remington can't? The pause was long as in several days, finally he replied well you can seat the bullets out longer allowing for a heavier projectile. Immediately I replied that only applies if one desires to be constrained by the magazine length. If I use it as a single shot I can seat just as long as the Creedmoor can. His response was "well nobody does that". Which I simply stated obviously you have never fired in a competition such as Camp Perry, or a NRA match. Everyone does do exactly that when on the long line. Regardless if 1903 series, M1, M14, or the M16 series. The silence was deafening, as I knew he had never done that. I closed with honestly it only matters if it matters, to a customer desires to do it in a certain way . Mimicking the design or thought process in the implantation of the design. Then of course he jumped on twist rate, again I shut him down.
Now understand I'm not condemning the 6mm Creedmoor or the ARC they do have a purpose. What I can see is the ARC simply like the Creedmoor allows a longer seating depth. To be used a shorter magazine or other defining limitations.
Just my thoughts as I have neither cartridge, although I can see where they are viable.
P.S. I have used CMMG products in the past, they have been great for a entry path (price point), as more affordable. Are they better designed? Not always, sometimes they have design limitations. But in fairness all do. I wouldn't shy away from their offering
Regards,
Mike
(I'm hoping some of the ARC shooters jump in here, and share their actual experiences with the cartridge)