when starting from scratch. Caliber 400 corbon. new starline 400cb brass. cci 500 spp. Oal-1.189. Bullet 155grxtp. No data for 800x in 400cb so I started close to high end 10mm data . ProChrono results..... 10grs-1254fps.....10.5grs-1324fps.....10.8grs-1373fps.....11grs-1427fps. Fired brass measurements and primers not all that bad. I will not push past 11grs anyway because theres no data from Cor bon pushing 155grs past 1300-1350fps with any powder. The last bump in powder 10.8 to 11grs gave the same 50fps rise in velocity as the 10.5gr to 10.8 did. How do you read this in terms of pressure? Cor bons data for the same with #7 is 13gr-14gr, 1250- 1300fps. Which I've also tested. Seems like a sharper curve at high end with #7?