Thanks, guys for some great advice. I can see the appeal of a 90, 95, or 100-gr. bullet, and you've suggested some good ones. I'm encouraged to learn that the Nosler 90-grain Accubond will stabilize in the 10 twist. The Sierra 85-grain HPBT recommendation surprises me a little. First, its hollow-point form seems a little odd for a hunting bullet. Wouldn't it do better with a more pointed tip? Second, its BC is very low (.311) largely because of its hollow point which would seem to limit its range. But perhaps its inherent accuracy makes up for this.
K22, when I mentioned "big deer," I guess I was thinking of some of the mountain mulies we have in B.C. that can go 250 lbs., although most are lighter than that. The other"big deer"species we have here are mountain caribou, and these can go 400 lbs. or more, but I think a .243 Win. is just a little too light for them. I've a .270 Win. and a 7x61 S&H that are more appropriate for caribou.