RE: 30/30 For Elk
I know a guy who has killed an elk 6 of the last 7 years with a 30-30 and open sights. Absolutely it is enough gun out to 100 yards. Would I ever use one on elk, probably not, but in the right hands, in close, they are just as dead.
As far as not being enough gun for deer, I would have to stronglydisagree (as would millions upon millions of deer). I once saw my mom kill two whitetail with 1 shot with her open sight 30-30. Aprox 70-80 yards, didn't see the second doe standing behind the first. Dropped the first doe in her tracks, and when we went up to gut her, realized that the bullet had passed through her and killed another doe about 10 yards behind her. Both were dropped in their tracks.