Just watched a fella take a cow elk with a Handi rifle on Carolina Outdoors on the Men's Channel. They didn't say what caliber it was other than a lighter caliber and they needed to get closer. He made a good shot, the impact wasn't dramatic, so I'm guessing a .243, dunno for sure, but she went down after running a ways and then they cut away and she was standing and fell over...hard telling if they took another shot or not, but the first hit was in the right spot.
