Welcome to LRH! In 1:10 I had good luck with 150 gr Nosler BT, I think they can do fine for game you are looking for, but I have never seen fallow or red buck in my neck of the woods. Searching Wikipedia largest fallow buck is about 220 lbs undressed, I think 130 gr bullets would serve you better, I've taken many whitetail bucks in same weight category + with 130 gr SGK, clocked at 3170 fps, of course for longer ranges you will need heavier bullets with better BC, so that's why I pointed to 150 gr Nosler BT, using 53gr of RL-17 I squeezed 3000 fps out of it, according to Alliant website 51.5gr clocked at 2,921 fps as safe point they say... Berger has 150 gr hunting bullet for 270 with better BC G1 0.531, but I never had a chance to try one... So good luck in your quest!