Its all about shot placement for me. wouldn't go lower than .243 though. In some counties here in Virginia buckshot is all you can use so keep it under 40 yards. About 5 years ago I saw a 300 RUM and had to have it. Don't know why but I did. I finally had a chance to use it 2 years ago in August hunting on a damage permit. I shot 5 does and not one took a step after being hit. I took one shot that I would never would otherwise and shot one of them as she was walking away from me straight up the arse and she never took a step. I'm a big believer in this caliber now.