My daughter has killed two elk with a 308 and 150 federal fusions one cow one bull. So not the same but probably somewhat comparable. On the bull she broke both shoulders with two shots. The only thing I didn't like was the lack of external bleeding, but the bull died in seconds.
The cow was one shot right behind the shoulder and it died in seconds too.
I've killed a few cows with my 7x57 and 150NPTs and of course they worked great.
I used to get really hung up on bullet selection but after killing and guiding to 50+ bulls and cows I care less and less about it given reasonable choices.
Get a good first shot and then if you still have a clear shot keep shooting until they are down and not moving.
Worry ALOT more about being in shape and your field shooting skills.
Last edited by Ralphie; 11/22/16.
