Upto griz either would be fine, however when your talking big bears I think 338 win mag or larger would be a better choice. If you have nothing now I would buy a 7mm rem mag and 338 win mag, this will handle your requirements and diversify your gun cabinet. However if you already own a 270, 308, 3006. etcthen keep it and go with 338 win mag. This equally serves the purpose and diversifies your collection. If your looking for just 1 gun to handle deer to grizzly, consider a 338 win mag or similar. IMHO the 7mm mag, 300 win or 3006 wouldn't be the medicine I would want in chasing a griz. Just like the often debate over the 270 for elk it can be done but is not opitimal. The biggest difference here is elk don't bite back!