Yes they're the same mag in every case I've seen. Like here:
https://dura-mag.com/duramag-ss-6-5-grendel-6mm-arc/
What should come as no shock to anyone is that Hornady has just announced the 22 ARC. It is in essence the 6mm necked down.
https://www.hornady.com/22arc#!/
Soon to be followed by .20 and .17 ARC and 6.35mm and 7mm ARC. Maybe 7.62 and 8mm ARC as well....
I’m excited, but I already have one, sort of.
Had a Cooper 22 PPC bolt gun 20 years ago, great cartridge, very accurate. Rebarreled a 6.5 Grendel AR to 224 Predator (22 Grendel). Also have Bolt guns in 22-250AI (similar to 22 Creedmoor), 22GT, 22BR, 223AI and 223. I’m a big fan of 22 cal bullets. 2 ARs in 6mmARC.
Although Hornady has some consistency issues with the 88ELDM, I think I have about 10k on hand, and about 5k of the Berger 85.5. My current PRS cartridge of choice is the 22GT, with the 22BR as a close second. GT can use standard magazines, while BR needs a BR mag kit. For PRS those two bullets are great, and the recoil (lack there of) allows me to watch the trace and target impact (or miss).
BL, I will not be purchasing a 22 ARC, because I have enough irons in the fire already. But I am a fan, and I think this is a better 223 than 223 Rem.
"Government is not reason, it is not eloquence, it is force; like fire, a troublesome servant and a fearful master"
22 Creedmore, 22ARC... I'm kind of hoping they would simply make some ammo available for us non reloaders. 6ARC has been round for how long now? Yet I still can't find much of it available. I think 2 weeks ago was the first box I saw at a local LGS. Even though I havent built an ARC upper yet, I thought about buying it for posterity.
I wonder if this will have the same reported high maintenance as the 6ARC? Dirty burning powders and difficult case-shoulder magazine to chamber transition supposedly makes the 6ARC not as forgiving of maintenance as a standard 5.56.
*note, I’ve never fired or owned a 6ARC, just repeating what I’ve seen reported on Sniper’s Hide.