I would use the 150 or 180 gr NP Nosler Partion. They stay together well on impact. I have been using them for years and taken many whitetails with 160 gr. 7MM mags and 165 gr 30-06. The 300 pack a little more punch and should be good for long range, open country muleys. You are better off with too much gun than too little. Just make sure the first shot hits the mark and you won't need to worry about a followup. Although it is funny how I alway feel the recoil at the range but never in the field:).

Tom C

�There are some who can live without wild things and some who cannot.�
Aldo Leopold