I'm long enough in the tooth to remember some of the early GUNS magazine articles on the lethality of the 100 grain 243 factory bullets on big and even aggressive game animals. The bullets used back then weren't nearly as good as present day bullets but they made mostly one shot kills on every animal they shot, from Jack Rabbits to Kodiak and Polar Bears. None of the animals they wrote about required more than two shots.
Like you, I've used both the 243 and 6mm remington, which give better velocities with heavier bullets, on everything from Marmots/Jack Rabbits to large Moose/Elk and Black Bears. The 243/6mmRem killed every bit as quickly as the 30-06 and my beloved 338-06. I'm not a magnum fan because I am recoil shy, but I've been on hunts with those that say they are comfortable with the magnums and their success/failures on game animals is proportionate to their shooting ability or in the odd case extremely bad luck. I recall a great Elk that was shot on the point of it's shoulder with a 150 grain 7mm Nosler Partition by my hunting partner, using a beautiful Winchester Mod 70 chambered in 7mm Rem Mag. The bullet hit was perfect and delivered at a 90 degree angle from a very slight shallow to the Elk on a slight knoll about 150 yards away.
The bullet penetrated about a half inch and the front end exploded, while the back of the partition took off at an angle into the unknown. The Elk spun around and ran. My partner was one of the best moving target shots I have seen. He put another bullet into the animal just behind the last rib and it exited just in front of the shot shoulder. The distance was 300 or so yards and the animal dropped immediately.
I had a 6mm Remington made up on a commercial 98 action and shot a smaller Elk the next morning. I was using 100 grain flat base Nosler Partitions at 3200 fps. The bullet broke the shoulder just below the joint and spun the animal around. It ran about 25 yards and stopped, then laid down and was dead by the time we got to it. The base of the Partition had kept right on and took out one of the major arteries under the spine.
Nope, I will not say the 6mm bullet did a better job than the 7mm but I will say it was every bit as much up to the task.
can do it but certainly prefer not too!
