When I inherited my Dad's .243 I naturally had to hunt it. It came with rwo boxes of 100 gr Core-Lokts. Worked out som me bugs in the rifle, mounted a proper scope (Dad was bad to cut corners on optics) and went afield.
First deer I killed, a 1-1/2 year old spike at about 50 yds, went down in a pile, shot through the near shoulder. Bullet was recovered on the off side, under the hide. Absolutely perfect mushroom.
Bamaboy went on to kill several more, all with the CL's, but we did not recover any slugs. I have since moved on to reloaded 100 gr Partitions, but I have no doubt that factoy CL's will be plenty for whitetails. I've set a Mossberg Mannlicher 810 with a fixed 6x, up this year with 100 gr Partitions.
NOte that with the .243, I think that the partion , bonded bullet or other premo, is not a bad idea. I'm inclined to believe that with calibers above .243, you do not need a premium bullet for a typical deer. But I believe 243 is near the cusp of "just enough" for deer. Combine its high velocty with its lighter bullets and you may have problems. The premo gives you a slight edge.