I've kilt 'em with 45 different cartridges ranging from .221 Fireball to .404 Jeffery. None have died any quicker than the ones I've shot with the .243 & 6mm.
I've kilt as well as with cal's .223,243 257, 264, 277, 308, 323, 338, 350, 366, 375,& 45. IIRC most died quicker from .264 up.
Course, there is something to be said for good shot placement and distance to target.
As always, your mileage may vary.
JAPPFT,
GWB
