Re: 243 max range
Looking at Remington factory ammo data, they have 80, 95 and 100 grain bullet options. All would be appropriate for shooting coues deer. Based on
Remington's ballistics, it looks like you can shoot all of them out to 300+ yards.
If you were to reload for your rifle, you could probably develop a load with 400+ capability.
I'm not gonna shoot here. I'm gonna shoot waaaaaaaay over there!