I was In The same boat not long ago but for a target rifle.I chose .243 mainly because I have lots of brass and all the reloading tools I need for it. Also every .243 I have ever owned shot very well. Can’t speak for the 6.5 as I have never owned one but after reading this thread I’m thankful I chose the .243. I’d look pretty stupid with a shaved head and a man-bun………