I would say anything in the 270 - 30-06 range would be good. The critical factor for heavier game like moose is bullet selection and shot placement/selection. I have 2 friends that use the '06 for everything. I tease them a lot but its all in fun. They always seem to get the job done. One recently took a 450 lb grizzly at 200 yds with one 180 gr bullet.