Originally Posted by toddconley
I can only tell you what the numbers are on my chrono. Could be defective.
My 7wsm will run 162s @ 2950 out of my 24in abolt with retumbo stuffed in the case. I think I have several loaded and may not need any this season but as soon as I start to reload for it we will be checking the velocity with rl 17. T
Have you shot your 7wsm and 280AI over your chrono in one chronographing event, and your 280AI read 3150fps and your 7wsm read 2950fps? If so, perhaps your chronograph is giving good data/speed.
The chronograph is the way to nail down the MV, above and beyond drops. Using drops to establish muzzle velocity involves guesstimation of both MV and BC. You need to establish MV over the chronograph - in my opinion.
Maybe you know someone else that will let you shoot over their chrono as a check on yours? What brand chrono are you using? "Never say never", but your 280AI MVs seem on the high side. Look forward to learning of your final determination.