Are you talking about the 6mm/.284 wildcat here? If so, there's NO COMPARISON at all with the 7mm Ultra Magnum! The 6mm/.284 is a high velocity round for sure, but it shoots much lighter, smaller bullets than the 7mm!! The 7mm Ultra would make a much better killer of deer-size (and larger) game at long ranges. The 6mm/.284 will cerainaly kill deer, but at long ranges ()400+ yards), after the small, light bullet slows down, it has lost a lot of the energy needed to kill things larger than varmints (coyotes, etc.). If you are talking about the regular .284 Winchester, it is a good deer load, but at extremely long ranges, the 7mm Ultra would have a definite edge in both power and flatness of trajectory over the .284 also!!

Keep yore powder dry!!