6mm ARC vs 6.5 Grendel

[dwinmeade]

I hear most people are having a heck of a time getting the Valkyrie to shoot any kind of respectable groups. Sounds like it's a super finicky round to reload for. Full disclosure I have no experience with the round personally. If I am incorrect, someone please let me know.

No sir, you are correct...I spent 6 months and many $'s just to get the Valkyrie to group at 100 yards...AND...never did. Sold it!

I wouldn't mess with the Valkyrie even if you gave me one...I'd sell that too!

 

[JASmith]

Longer barrels can give greater velocity for a given load. But shorter barrels usually give tighter groups. The point behind me cutting this barrel down that I have is to see what the FPS cost per inch is. With the 6.5 Grendel, FPS drops about 25fps/inch in the 16-20" range. Not worth the extra length for what I do, but to someone else it might be. I will post the numbers here when I whack this barrel down as I shoot it.

--HC

You can get a pretty good estimate of velocity loss (or gain) from chnagin barrel length here:

Estimating Velocities for Changed Barrel Lengths

The landing page you hit with this link has some example entry options. The Grendel is one of them, so you can easily check against your previous experience and get better confidence for the ARC estimate.

 

[Artpro]

For 500 yard+ shooting I would opt for the 6mmARC. I have been shooting a 6mmAR(Whitely) which is essentially the same cartridge, for over 10 years. It has proven to be exceptionally accurate with good ballistic performance at the longer ranges.

DITTO here1 I love shooting my Alexander Arms AR15. built with 24" heavy barrel. Its laser out to 400 yards, although a bit heavy to carry. Yotes don't care.

 

[SteelBanger]

Longer barrels can give greater velocity for a given load. But shorter barrels usually give tighter groups. The point behind me cutting this barrel down that I have is to see what the FPS cost per inch is. With the 6.5 Grendel, FPS drops about 25fps/inch in the 16-20" range. Not worth the extra length for what I do, but to someone else it might be. I will post the numbers here when I whack this barrel down as I shoot it.

--HC

Have you gotten this barrel length with velocity data yet by chance? I'm thinking about an 18" 6ARC build and would love to hear what speeds you saw at 18".

 

[belldar]

I was thinking of building a 6.5 Grendel but am starting to lean towards a 6 ARC build now. Sucks that ammo is way up there and hard to find right now but if I could find some brass I'll just load it up. I have a 6mm creedmoor custom I thought about parting with to fund the AR build. I have a bunch of the 95gr TMK(no not selling) that I think would shoot great out of the AR platform with a 16 or 18 inch barrel. This would be mostly for coyotes within 600 yards or so. I have not been a huge AR fan in the past but shoot them well and a 6ARC on an AR15 platform should be way more pleasant lugging around than the AR10 260 I used to have and hated. What say Yous? Possibly ditch the 6mm creedmoor(maybe keep) and build the 6mm ARC on a 16/18 inch barreled AR? Lightweight ARC build for 600 and closer suppressed. I already have a few 6.5 cals and the 6mm ARC kinda makes more sense for what I plan on doing.

 

[jasonco]

@belldar AR15, aren't that difficult or expensive to assemble, so keep your 6CM bolt gun. Having put a 6.5 Grendel together and after a year of load dev, it max effective range was just past 600 yds with carefully crafted 123ELDM and a 20" barrel. Not what I wanted. I had thought about changing it for a 6mmAR, but it wasn't worth cost. Then Hornady released the 6mmARC.

Love this AR, but the 6.5 Grendel, didn't live up to the hype.

 

[GRG]

I keep watching for brass as I want to do a 6mm ARC some time but seems to be hard to find. Loaded ammo is $29 though so have picked up a few boxes and will keep adding to it as that is pretty reasonable for brass and ammo for break in and to start out with. I have also read that the Hornady dies are working great so right now will just go with them as they are on the shelf as well. I'm just trying to decide on a bolt or AR. Never had a Grendel so not even concerned with the difference.

 

[belldar]

What barrel would you go with for the ARC? I was thinking JP bolt but not sure on a good barrel yet. Was planning Aero for most of the build unless there are other better ideas? Kind of keep the base part budget and figure on a better barrel and bolt if I can.

 

[BigNate]

Mr. Whitely initially developed/promoted the 6mmAR.

Hornady swoops in, changes the name to 6mmAR'C' and the whole world drools at Mr. Whitely's concept because of the Hornady name. Hornady gives no credit to Mr. Whitely, just copies his concept and calls it their own.

Shame, shame on Hornady!

FYI...Mr. Whitely has actually improved on his 6mmAR concept...the 6mmAR Turbo 40° Improved. (Hopefully this can't be copied without being so obvious.)

I am pondering an AR upgrade...it's between these 2:

6.5 Grendel...cheapest to convert, and tons of info/support/factory ammo.
6mmAR 40° Improved...not as cheap to convert, but it has the better accuracy potential.

It's what they're good at. Take a look at the 6.5mm Redding compared to the Creedmoor. That redding cartridge has got to be close to 50 years old.

 

[Wild Monkey]

Hornady lists Grendel @ 1028lbs for 400 Yards, & ARC @ 1038lbs for 400 Yards. Grendel gets the win for availability & ARC for high BC bullet capability. Frank Galli doesn't seem to find fault with the Valkyrie. 85 Berger, 6.9 Mils to 1000 yards, 7mph gun @ 600 yards. ( Believe the Target #38)