6mm PPC --> 6.5 Grendel --> 6mm ARC - Why?

[Fess]

Maybe some of the current powders already contain the secret sauce? I load for 30-30 and until Leverevolution powder became available to the reloader, it was impossible to match Hornady's factory loads.

[grayfox]

Lever is definitely the hot tabasco for the 6Arc...
Hot in terms of achieved MV not necessarily chamber pressure.

[biodsl]

Hornady has made claims that a significant part of the 6ARC's performance comes from the custom blend of powders they use that is not available to reloaders. Have you had any difficulty replicating Hornady's velocities with published, pressure-tested loads?

I haven't experimented much. I'm actually exceeding book velocities with 29.5grs of Leverevolution under a 105 Hornady. This load is giving me 2570-2580fps from a 16" Lilja barrel. The trajectory for this load is pretty close to identical to my 123gr ELDM load out of my 22" Grendel.

[SDguy]

6ppc did great in a bolt gun at short range due to slow barrel twist rate. Pressure capacity of the bolt gun will out do pressure capacity of the gas gun lower limits. 6mm ARC does well in a bolt gun as well & does better at distance due to faster twist which handles longer higher BC bullets. Grendel does great as well with more momentum on target at short to mid range.

All good options for something & each crosses over to one degree or another.

I have been wanting for a fast twist 6ppc for a few decades for a long time. 6 Arc was the easy button for a fast twist 6mm ARC. Still taking too long to get ammo & firearms to market. I was more interested in a mini action bolt action 6mm ARC & a drop in Pac-nor barrel was my path to a 6mm ARC.

Never had a 6ppc. did a few CZ527's in 6.5 Grendel & have now done one 6mm Arc on the CZ 527 action. The lower recoil is favorably noticeable with the 6mm ARC & as a whitetail deer rifle I don't feel compromised whatsoever. Bullet selection is good for both, though IMHO the ARC is at an advantage here as well.

In an AR I am unsure if all of my bolt action experiences would transfer.

If you are not a reloader then Grendel, would be your better choice at this time IMHO.

[Lemonaid]

Getting back to the O.P.'s question. New bullets in 6mm that required faster twist barrels made the 6ppc (with a fast twist) and 6 Arc better at longer range than 6.5 Grendel. An example you can plug into a ballistic calculator is a Barnes 112 match burner (b.c.=.624) going at 2650 fps. This I got from my 24 inch barrel 1-7 twist 6 ppc bolt action. Even with the same barrel lengths in an AR platform, with the higher b.c. bullet in 6mm you get some extra yards before subsonic.
Now add in that Hornady can put out a new shiny product and make more money and here we are.