Stone Cold-I speak from experience as I own two 7mmstw's and a 7mm ultramag.I handload both to higher velocities than you can get with factory loads in your ultramag and shoot both to 500 yards on a regular basis at my local range.With a zero of 2.75" high at 100 yards and 140gr ballistic tips all three of my rifles are 18" to 19" low at 500 yards.The numbers you quote are simply not possible.I have no doubt that you did hit a coyote at 550 yards but there is not a cartridge available that can produce enough velocity to be anywhere near as flat shooting as your numbers indicate.When you shoot some groups at various distances you will see the true trajectory of your cartridge.