What is the purpose of the new rifle ? There are much better cartridges out there than 6ARC and 6.5 Grendel which are compromise cartridges made to function in an AR15 .

6BR , 6 DASHER , 6 / 6.5 x 47 , 6 / 6.5 Creedmoor, 260 Rem are all better choices in a bolt rifle .