6 ARC - Anyone Regret It? Also considering 22 ARC

[LRRPF52]

Factory 22 ARC ammo in 88gr is being reported at 2850 by consumers. Is 6 ARC 90gr ammo shown to be faster by consumers?

6mm ARC has less case capacity than 224 AR/22 ARC, which could even them out. You can amend my statement based on that for the 6mm and 22 variants since I’m used to 6mm AR data going back over the last decade+.

As a general rule though, as the bore diameter/volume decreases, the velocity for the same projectile weights decreases due to overbore choking the amount of pressure that can safely be relieved.

For example, factory 90gr TNT from Federal does 2900fps from my 17.6” Grendel, and 2700fps from the 12”. BC sucks compared to 90gr in 6mm and .224, but it sure loves to be punted out. If you made a streamlined 90gr 6.5mm with a secant ogive and long boat tail, it would be competitive with the others without needing to chase pressure.

 

[JR1200W3]

6mm ARC has less case capacity than 224 AR/22 ARC, which could even them out. You can amend my statement based on that for the 6mm and 22 variants since I’m used to 6mm AR data going back over the last decade+.

As a general rule though, as the bore diameter/volume decreases, the velocity for the same projectile weights decreases due to overbore choking the amount of pressure that can safely be relieved.

For example, factory 90gr TNT from Federal does 2900fps from my 17.6” Grendel, and 2700fps from the 12”. BC sucks compared to 90gr in 6mm and .224, but it sure loves to be punted out. If you made a streamlined 90gr 6.5mm with a secant ogive and long boat tail, it would be competitive with the others without needing to chase pressure.

75gr out of 22 Grendel is around 3100 pending barrel characteristics. I'm betting an 80gr ELDM is easily 2950-3000K without having to push past 60K psi