I am back from my second range test. The cases used were fire-formed and had 2g H2O increased case capacity.
Load was increased from 55g to 57g IMR 4895. And, velocity increased from 2932 fps to 2970 fps.
This already exceeds the published max velocity of the 300 Win Mag with the same bullet and same powder.
No signs of excessive pressure and easy extraction. Next outing will be increased to 59g.
I am really starting to like this rifle ... a lot.

http://www.buckstix.com/buckpics/COUGAR-TARG-1-SM.jpg

[Linked Image from buckstix.com]