6mm ARC vs 6.5 Grendel Sanity Check

[biodsl]

12” 6mm ARC
6mm 108gr ELD-M, 2350fps hand load with CFE223 or LeverEvolution, 23.8” Hg (higher altitude/lower air density where I shoot a lot), 59 deg F

12” 6.5 Grendel
107gr SMK, .230 G7 BC model, 2475fps hand load with IMR 8208XBR (~ 49,000psi), 23.8” Hg, 59 deg F

The Grendel has a 125 fps advantage over the 6mm ARC with similar weight bullets?

I'm getting 2560 fps with the Hornady 6mm 105 BTHP with Lever out of a Lilja 16". I wonder if the 2350fps figure you've got is low.