I Have heard thet carabiou are not hard to kill,but the range can be a little on the far side.Since moose are also on the menu I would go with the
300 Win Mag and a good 180gr Nosler Partion sighted in for 2 in High at a 100 and dead on @ 250 and about 7-8 inches low at 300 yds.
This should work good,also remember the rain gear.
BBJ