There are two distinct types of 243 ammo. These are varmint loads and deer loads...
Anything on the lighter side, meaning 60 to about 85 grains, usually is intended for coyotes and other smaller game. In general, its light, very fast loads with rather fragile, rapidly expanding bullets. These guidelines are kind of general, but overall, using one of these on deer is a big mistake..
Heavy for caliber tends to be loads more designed and intended for use on deer. 243 is a very capable deer cartridge BUT it absolutely must have the right bullet. This usually means something in the 90-100 grain range. Pure copper monolithic bullets like the Barnes TTSX sort of violate this rule and often run a little bit lighter, but that's because monolithic copper acts differently than jacketed lead...
A 6mm 243 diameter bullet isn't big. If I fire a 180 grain .30 cal out of a 30-06 or 300 Mag at a deer, and I loose half the bullet weight, I've still got a 90 grain rear section that can keep driving through the deer, make a big exit and leave a generous blood trail if everything goes sideways. There is room for error. However, that 90 grain rear section, which is basically leftovers from a bullet failure, are still roughly the same size as the typical 243 bullet BEFORE it hits and expands. And if you loose half a 80 grain out of a 243, you've only got 40 grains left (.22 LR anyone?) and a microscopic pinprick exit with little blood trailing. My point?: there isn't a large amount of 'extra capacity' or room for error with a 243.
I'd deliberately be looking for a very very "good" bullet. Top choices would be Nosler Partitions, Nosler Accubonds, Hornady Interbonds, Barnes TTSX, Federal Fusion, Federal Trophy Copper. I'd be 1005 happy with any of those. Take your pick. If I'm launching a 90 grainer at a trophy buck, I want most or all of that bullet to remain intact and do the job.