I have had a 7mm Weatherby for about 25 years.
I have used mine primarily to hunt whitetails but I have shot a couple of antelope and a few mule deer with it as well.
I have always used RL22. I have had good results with the 160 Nosler Partition, the 154 Hornady and 140 Ballistic Tip, Accubond and Partition. They all work very well on the animals I have used this rifle on.
Enjoy your new rifle!