Those are velocities from a 7 1/2" barrel. And yes, it was just one bad shot as far as the velocity variation goes.

I'm somewhat surprised by the velocities, I have notes from 1995 that show 1500fps and SD of 20 with slightly more 2400 and CCI magnum primers. In fact, my records show a 275gr bullet at 1260fps and SD of 12 with 16.5grs. of 2400 and magnum primers. It's hard to believe the primers would make that big a difference. Maybe I need to do a little side by side comparison and see what I find.