Beginning hunter going on my first guided hunt in the Bridger range of Montana. My rifle is custom built 6.5 PRC that I will be using. I have taken a long range class but will limit myself to 500 yards. Which bullet should I use? I have developed loads using the 143 ELD-X and 147 ELD-M. My gunsmith slightly favors the ELD-M as he has had better pass through using that bullet. For my max range is there a better bullet that I should try?