oh god..... 243 rant time. The .243 is not anything more than a foxing calibre that's good for roe. Comparably a 17hmr shooting roe deer is more powerful than a 243 shooting a red stag, here's you maths and no I'm not saying it is legal or acceptable to shoot a deer with 17hmr:
17hmr v's 40lb roe deer (assume for the story it's a 'hunting' style bullet not v-max)
Bullet energy at muzzle 240 ft/lb
Deer live body weight 40lb
Energy delivery = 6ft/lb per live weight pound
243 v's 300lb red deer (assume the bullet actually meets legal energy in England for the large deer1,700ft/lb)
Bullet Energy at muzzle 1,700ft/lb
Deer live body weight 300lb
Energy delivery = 5.7ft/lb per live weight pound
Er hello, your .243 kung foo is not strong..... it is weak like baby mouse!
If you don't believe me about the energy to live weight correlation then consider the reaction of the example deer shot with the energy discussed assuming a 'good' chest shot. Both deer will jump and run before collapsing shortly after, but hit them badly and you're looking at a wounded and suffering deer if a lethal follow up is not made.
There is an elephant in the room which you forgot...
So consider shooting an elephant with a 416 Rigby. 400gr ME=5115ftlbs.
Elephant weighs 3 tons (2240x3=6720lbs)
5115/6720=0.7611ftlbs/lb.
1,700ft/lb)

