Thread: New 6mm ARC from Hornady

This might excite some of you

I will admit, this has peaked my interests!

Its a renamed 6mm Grendel. I have the reamer and a CZ 527 barrel chambered in it if you want to test shoot it.
You can use a 6.5 Grendel bushing die with a 6mm neck bush to resize them.
I also have the little sister cartridge .22 Grendel

Maybe I'm not looking hard enough but what does the 6mm ARC give that the 6.5 Grendel doesn't?

It will do better than the 224 valkyrie did, its supposedly designed to run good through an ar, which is a bit redundant here now sadly, i think the 6gt, 6 creed, 6xc, 243 etc will keep it down here in nz. But in saying that, it will go bang and thats always a good time

But what will it do that 243 wont and we dont have AR's to run it in anymore so its just another good sales thing by Hornady for the US market .

Originally Posted by Spoon

Maybe I'm not looking hard enough but what does the 6mm ARC give that the 6.5 Grendel doesn't?

Speed, higher BC and retained energy.
Equal bullet weight comparison as follows:
6.5 grendel with 107gr TMK, 2550fps

6mm grendel with 108gr ELDM 2700fps

@Wingman with you being in the Waikato, that offer might be a little hard to turn down!
Do you have the barrel currently fitted with some loads ready?

Always enjoyed following your different projects!

Originally Posted by kiwi-adam

@Wingman with you being in the Waikato, that offer might be a little hard to turn down!
Do you have the barrel currently fitted with some loads ready?

Always enjoyed following your different projects!

Yes I think I have some 95gr TMKs or noslers loaded up and barrel can be fitted in about 30 seconds.

I stand corrected..
In true Hornady fashion they have not just necked down a grendel case.
To maximize on factory ammo, dies and brass sales they have made the base to shoulder dimension shorter than the grendel case but longer than the 6ppc case.

The 6mm ARC is judging by the SAAME listed case head dimensions and the Maximum Average Pressure (MAP) of 52,000 psi, it is based on the .220 Russian case (like the 6.5 Grendel or 6mm PPC). At first glance, the 30-degree shoulder angle and the shoulder diameter of .4301″made me think that 6mm ARC is a necked down 6.5 Grendel, however, the length to shoulder is 1.1207″ which is shorter than 6.5 Grendel’s 1.1507″ (and longer than 6mm PPC’s 1.075″).
The maximum cartridge overall length of 2.26″ (57.4mm) is identical to the max COAL of .223 Remington which means 6mm ARC is designed to be an AR cartridge. The case length of 1.49″ results in a lot of bullet space (.77″ or 3.16 calibers) which will allow loading projectiles with very long ogives and great external ballistic performance. The SAAMI drawing states a muzzle velocity of 2,700 fps for 108-grain bullets.

243 caliber cartridges based on the .220 Russian case have been successfully used by competition shooters with the most popular of them probably being the 6mm PPC. There are several variations of 6mm PPC in the CIP standards, however, oddly enough, neither 6mm PPC nor any of its siblings are standardized by SAAMI. That being said, the 6mm ARC looks like an attempt to have a SAAMI standard cartridge of this very successful case and caliber combination.

Mean. Another good match for a mini action. Should have a pbr advantage over the 6.5 grendel. Be a mint mid to lr varmint round

Originally Posted by wayno

But what will it do that 243 wont and we dont have AR's to run it in anymore so its just another good sales thing by Hornady for the US market .

Fit in a mini action. Fire a 6mm bullet out the end using less powder at close to similar speeds with less throat erosion.

The little 6mm varients are all very usefull little cartridges, be great if one of the versions found commercial success. Hornady has a clued up marketing department that's for sure

That is some great marketing.They could have called it a .243 Short, which, although honest, simply won't win any supporters. The AR aspect is pretty much dead in NZ, so it will only really have appeal in mini length actions. I like the short action rifles, and would really consider this as an option, but that depends heavily on availability of components.

"however, the length to shoulder is 1.1207″ which is shorter than 6.5 Grendel’s 1.1507″

One would imagine this dimension is necessary to minimise the chances of Billy-Bob trying to fire the 6.5 Grendel in the ARC chamber. Could get exciting in a bad lawyer driven way if they succeeded....

I've long been daydreaming of building one of the 6mmAR variants or 6mm Grendel on a Mini action. If the ARC becomes available as a factory chambering, Hi-Tec puts out a stock and fit one of the flush floorplate setups, that will be very sweet!

Faster, flatter trajectory, better sectional density, better BC. Military application (which it's designed for) better penetration