Thanks for the replies.
After I posted this I said
its going to be every bit as effective as a .243 on deer sized animals.
I plan on using the 120grn Barnes TTSX for elk.
I'm having a hard time with ballistic coefficients and believing high BC are really even significant for my 300-400 max range big game rifles. I'm not a long range shooter. I'm sure they do matter and make significant differences out beyond 400.