I own a Ruger 7mm Magnum. I have a box of Winchester Supremes. 160 grain. I'm going bear hunting in 2 weeks. Are they heavy enough, or should I buy a box of 180s (or heavier)? I drew a Coues tag - are the 160's too much for Coues? I guess - I'm cheap, and lazy. Is there one cartridge that would be an acceptable compromise for both, so I can just sight in the rifle once??