:grin: By God it better be gettin' close to hunting season!
I too will be using my .243 Ultra Varmint for deer this year. I've only used 100 grain bullets for anything I've hunted, which includes whitetails, mule deer and elk. Yes, I, like many others have shot and cleanly killed elk with a .243.
I'll admit, I've never gotten a monster bull, but I have taken bulls with it. However, I've never been fortunate enough to see a really massive bull in the wild.
I don't have any experience even shooting 85 grain-ers, so sorry, can't offer any advice other than that your .243 will take deer no problema.