06-10-2020, 11:51 PM
The 6.5mm Grendel was made by stretching the shoulder of the 6mm PPC longer by 0.0757" to increase case capacity and necking it up to 6.5mm. The 6mm Grendel is basically that cartridge necked back down to 6mm. The 6mm ARC is a 6mm PPC with the shoulder stretched by .0457", exactly 0.030" less than a Grendel case. The big difference is that it's now a SAMMI specified cartridge and so will probably get wider adoption. We will have to see what impact this has on the old Grendel type 1 vs type 2 bolt issue.