Primers, powder, and some brass is tough to come by. And has been for a long time.

No, the reason to design something new is to correct inefficiencies and/or problems of what was currently available.

I still can't understand why you push back so hard on American engineers, that are coming up with new ideas.

Oh wait, I just remembered something...

From the consumer's perspective, the value of any product or service can be measured in terms of utility and warranty. Utility is defined as being "fit for purpose", while warranty is defined as "fit for use".

What is the purpose behind this new cartridge and how will its use offer the shooter or hunter anything above what is already available to them?

No question the folks at Hornady did a great job getting hunters to see the 6.5 Creedmoor as a more accurate (warranty) cartridge that would make them a better hunter (utility). The fact they probably already owned three or four rifles that were plenty accurate at the shot distances they most often take is besides the point.

And the case geometry is so good, the case has been wildcatted 3 times already, in only 13 years. Not the first time I've written that either.

For those that want to dig into this. Because Dan elicits the same response, but does not pay attention to the response.

Go back to 1906 A.D. what is the shoulder angle on the .30-06?
In 1952, what is the shoulder angle AND bolt face of the .308 Win?
What is the shoulder angle of the .270?
What is the shoulder angle of the .280?
What is the shoulder angle of the .243, the .257 Roberts, the .260 Rem, the 7mm-08?

In 2007, the 6.5 Creedmoor, what is the shoulder angle?
The 6.5x47 Lapua, what is the shoulder angle?

Look at the 26 Nosler, 28 Nosler, 30 Nosler, 6.5 PRC, .300 PRC, what's the shoulder angle?

Now, in 2020, look at the same things about the 6mm ARC. Bolt face, case length, shoulder angle.

Why the shoulder angle, and case body change? It is more efficient.

Show of hands, who daily drives a vehicle over 20 years old? I know already know the answer. Who here daily drives a vehicle over 100 years old? No one, why? They're worn out. But if they weren't, one built in the last 10 years is far more efficient, more capable, and more comfortable to drive.

It is all called progress. Progress gained from experience, lessons learned, and experimentation. I will never understand those that choose to begrudge those that achieve these things for the betterment of the rest of us. It is as American as apple pie.

Hornady planned to release this in march at teh NRA Convention and that fell through with Covid shutdown at that time, then came necke down, 6mm Fatrat the big gun and ammo run putting about all manufactures behind wand with Covid concerns to go along with that. Hornady has been making the Grendel for years and were the first t produce factory SAAMI ammo for it and developed their 123gr 6.5 bullets for it that have done well.

The Grendel case is based on a ppC case with the body lengthened and to hole a 6.5 bullet. There are several different wildcats using the same case. 22 Grendel, 6mm Fatrat (improved Grendel case) 6mmAR simply a Grendel necked down, 6mm Fatrat (improved 6mmAR) Grendel MAX which is just an improved 6.5 Grendel, a 277 version, 30 cal and .358 and those are just the ones I know of. Now Hornady shortened the 6mmAR by .03 in body and case lenght for the ARC.

There is some Hornady data for the 105 and 108gr bullets on their site but not for the lighter weight bullets. LINK

Reports I have seen on factory loads from Hornady are about like the last time I coroned some Hornady Grendel loads over 100fps extreme spreads from the dame box. Sometimes I think Hornady os trying to make things too fast or something. But even at that one reported sub MOA from his new barrel at 300 yards which is not that bad for new AR Barrel and factory ammo.

From the looks of Hornady data it looks like they might be using LVR powder for their factory loads which could kinda make sense.

I may be wrong but think the reason for shorting the Grendel case that .03 was to use the longer 108 bullets nd have the full chank of the bullet in the case instead of changing the bullet and loosing a little BC which they did not want to do in order to get what the Military was looking for out of an AR, otherwise it would be simple to just standardize the 6mmAR. Many of our SAAMI factory cartridges were the result of reloaders wildcatting the current cases at the time.

I like the fact Hornady continues to innovate as JG and Kmon1 have indicated. It is good for the consumers. This is the first cartridge since the 6.8 SPC that I have been excited about and will probably get one eventually. My gut feel is the 6mm bullet is optimum for an AR15 platform.

X2

Public Service Announcement :

Seems possible that Odin Works barrels have a short throat / chamber , multiple shooters reporting Hornady Black 105s getting stuck in the lands and powder spillage

Once this is has reasonable availability, I'm definitely in.

This is why I never jump in early. Things get rushed out too quickly.

Wise words....

Here are a few photos of my first range trip today with my 18” Proof Research barrel - mind you Proof has been working with Hornady during development of the caliber well ahead of the release for public consumption.

Well despite all that R&D and big marketing campaign it didn’t prevent me from spilling powder into my upper and lower and using a cleaning rod to clear the bore - TWICE.

Looks like classic oops screw up. Somewhere in the chamber/throat on those or the ammo is off. Something is not right

I just got in 4 boxes of the Hornady Black and a Faxon/Brownell's 14.5 heavy barrel...should be able to do some testing this weekend

I had chambered a few of the 105 BTHP (Hornady Black) rounds at the house and they didn’t have a problem being extracted.

It wasn’t until the range trip when the rifle was cycling and feeding from the magazine that the problem occurred.

At this point I’m betting on ammo being the issue.

TexJitter: Measure your COAL on the factory ammo , I hear hornady might adjust them to shorter soon...

Mine measured between 2.2485 - 2.2515 “

I would call before ordering just to be sure it is in fact new unprimed brass , if anybody orders and receives please post back here that it is confirmed 6 ARC brass.

Too expensive for me after shipping and credit card fees.

https://www.gunbroker.com/item/876883344

Concerning factory ammo sticking in the lands of some barrels....

Here is a video I made of my proof having problems with 105 Factory Hornady Black and below the video is a recap of a phone call with a Hornady tech this

8/18/2020: I just got off the phone with Hornady.

They are not completely putting ODIN and Proof in the hot seat - the tech says they could stand to shorten the COAL for the 105 BTHP Black ammo.



He says what most likely happened is that Hornady sent “high speed reamers” out to barrel makers, these reamers are good for only 10-15 chambers (they are non-carbide).

It may be that these gun manufacturers went in to full production with these high speed reamers and so early runs of barrels can be short or tight in the throat.

He says I can seat the factory loads deeper to use what I have and I said no thanks.

He said maybe chasing the throat with a carbide reamer will fix my barrel and I said I wouldn’t want to do that to a 500 barrel.

So now waiting for proof to respond....

Update again - proof responded , they don’t have any 105 BTHP on hand to test barrels with, they requested photos of a chambered round which I will send to them shortly.

Meanwhile.... I talked to another barrel maker who is working on a barrel for me and they said they’re aware of the “issue” and they think the bullet diameter of the 105 grain BTHP is towards the higher end of tolerance.....

Continuing to trouble shoot this .

I finished up my build of the ARC, grabbed my single box of Black ammo, scooted out to the range and began testing. First shot fired, but didn't eject. I couldn't pull the bolt open with the charging handle, I had to pry it open. Shot one more round with the same results and decided something was terribly wrong! The primers were totally pancaked and the head stamp was battered. I pulled down a couple of the rounds and weighed the powder charges: first one was 25.3 grains; second one was 28.8! I went ahead and measured the COAL on the remaining pieces and it varied from 2.250 to 2.285. Next I mic'ed the cases: 1.485 to 1.495; not a particularly high variance, but the SAAMI spec is 1.490. In my opinion, this box of ammunition is dangerous trash, and I'm really disappointed that Hornady let it get out. I'm sure they were rushing to meet demand, but that's no excuse, imho.

FYI, this was Hornady Black, Cat. # 81604; Lot # 3201395

To fix the problem, I first dropped the COAL to 2.2 on a couple of rounds; that didn't fix the extraction problem.
Next I trimmed a couple of cases down to 1.482; that didn't fix the problem but the bolt became easier to open
Next I built two rounds with 25 grains of the powder I recovered, put into two cases that I had trimmed to 1.482, and seated the bullets at 2.20; didn't fix the problem but the bolt was at least short stroking, trying to eject.
Opened up the gas block a tiny bit, and, bingo, the machine began to operate properly. Since I still haven't gotten the dies or the brass that I ordered many moons ago, I was having to do all this experimentation with that single box of factory junk. When the dies arrive (?), I'll continue my testing and share any information I gather from that work.

Let Hornady know about that 3.5gr is a huge variance in powder for that small case

Anybody see the Hornady reloading data for 6-ARC (gas guns).

If you did , want to talk about FALSE ADVERTISING

I’d be a lot more interested in this round if I could see the speeds for a 78g Vmax, the 100+ grain rounds do nothing for me for coyotes. If I want heavy and slow I’ll shoot my Grendel.

Hornady says the 75 grain V-MAX can be pushed to 3050fps with 33.5 grains of LEVERevolution. Didn't see a 78 grainer in their latest data.

I didn't find AR-15 load data Wade but did find this for bolts. Should be a potent little varmint cartridge in an AR platform.