Went to the range yesterday to work on my drop charts with 215 Bergers in my 300rum. I set up both of my chronographs two feet apart about 10 feet in front of the muzzle. Older chronograph is a pro chrono, and the newer one bought last year is a Chrony F-1. First shot showed 3075 through the Pro Chrono and 3163 through the Chrony. Then I put the 338rum in front of the chronographs and recorded 2780 through the Pro Chrono and 2870 through the Chrony. My 338 rum loads have been proven out to 1250 and the velocity comes out to 2830 with the 300 gr Berger OTM Hybrid gen II. With the numbers entered into exbal on my PDA, using 3025 as the velocity for the 300 rum with the 215 berger I am hitting a consistant 3 inches low at 690 yards. I need an additonal .25 moa up to hit the mark and to get there, I think my calculated velocity needs to go down to 3000. Anyone else out there with Chrony's have them showing fast like this?