Hornady load data over max pressure in QuickLoad

[Patrickb4365]

Hey. I picked up a CMMG 6mm ARC 20" (Endeavor 300 series) AR-15 this year and am in process of developing loads for it. I also just purchased and am learning the QuickLoad software.

I'm using the Hornady 108g ELD Match bullet and Varget.

Hornady lists a starting load of 24.5 (2,200 FPS) and max load of 27.2 (2,450 FPS).

When I model the max load of 27.2 QuickLoad shows that as way over max pressure at 59,033 psi. Gas gun maximum pressure is 52,000 psi.  So this surprises me and makes me wonder that maybe I'm using QuickLoad incorrectly or is it simply inaccurate when estimating pressure or is Hornady publishing loads that are over pressure?

According to QuickLoad I'd have to reduce the Varget charge from 27.2 to 26.05 to get under the 52,000 psi limit.

QuickLoad has the 6mm ARC cartridge at 34.5g water max case capacity.  I've read that it might actually be 34. If I change QuickLoad to 34 it estimate the pressure even higher. I haven't measure my Hornady factory brass for capacity. 

Any theories on this or experience using 6mm ARC in QuickLoad and have suggestions for improving the QuickLoad results?

I'll include a screen shot of my QuickLoad settings and here's a link to image in case it doesn't show up here.

Thanks.