You can definitely push the velocity higher with Lever than Varget.
I set up my ARs with trued actions for full bolt lug contact, so I'm not as worried about breaking a Grendel bolt. As for pressure limits, the weak point is the Grendel case web and the primer pockets; you'll see loosening primer pockets first, and then expanding case heads on Grendel brass before you reach anything approaching dangerous pressure for the rifle; I would be using the same loads in a bolt action as in these ARs. It's pretty easy to work up until primer pockets just barely start to loosen a bit, and then back off. The first part of my load development with wildcats like this is to work up to max loads, seating fresh primers in each case after firing to test the pockets. When they get easier to seat than the first time, (using known new or once fired brass), that load or a little less is max. I've never run into any safety issues doing that, and generally try to settle on a load that gives at least a few loadings without loosening primer pockets, and that'd be a top end load.
I have not used Starline brass in this cartridge, but Lapua brass is generally accepted to be on the smaller side for case capacity. Anyway, the loads above were actually in Fiocchi x39 brass.
I can say the new barrel is showing signs of a little higher pressure (better fillout on those fireform loads) than my 24" barrel; the new barrel has less than 10 rounds through it while the 24" has been in use for a couple years. If your barrel is new, it may be more like my 20", and seem a little hotter for the same charge than my 24".
Last edited by Yondering; 12/23/19.
