When I was stationed in Washington I used a Savage 99 in .308 with 180 gr. Just incase of bear or bigfoot. Ok I was young. It did a fine job on blacktails that were good sized deer to my standards.
No thats not too much I have lived in western wa my whole life and have seen a huge variety of calibers hunt blacktail. From .243 to .300 win mag plus lever action and slug guns in various calibers. The .308 is a pretty common round to use for blacktail. I use a 30-06 and have used a 7mm rem mag to take smaller blacktail. No massive waist of meat like you hear of happened.