First of all, by all means drop down to 150gr or at most 165gr bullets. Also, go to something in the more premium category such as Hornady SST or Interlock, Speer Grand Slams (Nitrex), Federal Classic (Sierra Pro Hunter), Federal Premium (Partition or Ballistic Tip) or Remington Premier (Partition or Ballistic Tip).

These will all give better performance than 180gr Remington CoreLokts.

Good Dogwork and Good Hunting