SAAMI Approved: 6mm ARC
 

SAAMI just published drawings for the “6mm Advanced Rifle Cartridge.” It’s a 6.5 Grendel (7.62x39mm, 220 Russian) case with the shoulder pushed back, taper slightly increased as the shoulder diameter is the same as the Grendel, and naturally, necked down to 6mm.

SAAMI Drawings for 6mm ARC

Speculation is that Hornady is involved (wholly unsubstantiated at this point), as a major driver for pushing the shoulder and neck back MIGHT be to accommodate long ogive, heavy for caliber 105-115 class, high BC bullets like the 108 ELD-m, but still remain within COAL maximums for AR mags. Early speculation also expects it should run somewhere around 2700fps with the 108 class bullets, giving it considerably greater super-sonic range, with less drop and drift than the 6.5 Grendel parent.

Some folks might recall my enduring lust for a few years for a 6mm Grendel variant, and that I finally built a 243 LBC last year. I’ve long considered a 6mm Grendel to be about the ideal mix of speed and bullet weight from the 2.3” class of cartridges, and I wrung my hands for about two years because I didn’t want to be locked into any single source, proprietary cartridge. This cartridge will have slightly less case capacity than the 243 LBC, so I’d expect it to give up around 100-150 fps to the longer LBC (or doppelgänger 6mmAR). The 108 ELD’s tend to run considerably slower than I can push the 105 Hybrids, which I push to 2900 with the LBC case, so I’m thinking 2700 with a 108 ELD seems pretty reasonable. I’ve considered the 6.5 Grendel/6 Dasher/6 Creed/243win class of cartridges to be optimum for deer hunting, and this entry into that class will be fantastic for sport shooters and hunters alike.

I’m thoroughly excited about the prospect of a CZ 527 Varmint Tactical in 6mm ARC in the near future!

Ya gotta post some pictures man. I'm already drooling.

This sounds interesting. 6mm seems to be that sweet spot in cartridges.

I wish I could do better, but the only solid info I have on the new 6mm ARC is the SAAMI drawing page I linked above.

I think I’ve shared this photo of my first dummy round for my 243LBC here before, but this would ROUGHLY approximate what the 6 ARC will look like - only a little longer. This is a 105 Hybrid seated to mag length, and you can see there isn’t much bearing length left before the ogive would slip into the case mouth - which is why I suspect the SAAMI submission, whoever made it, includes a pushed back shoulder compared to the 243 LBC pictured here.

A post over at the Hide is suggesting Hornady is, indeed, behind or at least involved in the submission.

That ought to help things along. Hornady has a good rep for this kind of stuff.

Scuttlebutt: the SAAMI approval came late in Jan, and things weren’t ready to drop at SHOT. Now, with the CV economic dip, school closures and job losses, and social media sensationalism of it all, Hornady is parlaying launch until we can step outside to confidently breath fresh air, and have some money to spend.

Since it’s so very close, but a step smaller than my 243LBC, I’m not sure I’ll buy a barrel when it does drop, but I do expect, eventually, most barrel companies will simply stop making the 6mm Grendel Wildcats in favor for the standardized cartridge. That day, I’ll cry over 50-100fps, buy a new barrel and dies, and party on happy.

Well the cat’s been all but fully out of the bag for some time now, as we’ve seen brass, reamers are for sale already, and it’s all but officially announced...

Well it appears we won’t be waiting much longer, as Hornady dropped their teaser video promising to satisfy our curiosities next week:

Interesting Twist
 

Well the cat’s fully out of the bag now. What I found interesting in the Hornady announcement is that they developed the 6 ARC after a DoD request for a replacement to the 308, fitting into the AR-15, for some unspecified application.

It’s also looking like the velocity spec for the 105 and 108 factory ammo is a bit better than previously expected. 2750fps with the 108 ELD is no joke - transonic boundary past 1250yrds! I’ve had the 108’s out to 1400 when pushed to 2900 - but I was burning 10grn more powder to do it.

https://www.hornady.com/6mmARC#!/

They state right in the promo materials they used a 24" barrel to obtain those velocity figures.

To me, as a guy that is mostly from the military/tactical arena (I'm ex infantry), this round is a solid blah.