OK, i see you're from B.C., not Montana. A 7mm will get the job done, if your shot is on. And if your shot isn't on, you have got to use good judgement in what you do after the shot. Apparently you guys are far from sure on where your hit was. Just because the bear ran off after two hours really doesn't mean much to me other than you didn't get a heart shot. With a 7mm, I think a griz with one lung will easily go for two hours after the shot. And a gut shot bear even more. The reason you are not finding much blood is more than likely due to the fact that you dont' have an exit hole, and even if you did, the fat on a bear plugs those holes fairly quickly. You should still be out there trackin.