If its a modern .50 caliber, most shoot pretty good with sabot xtps and 100 grains of pyrodex or two pellets. I've also heard good things about powerbelts.
I ended up getting the White Hots since several others claim it burns much cleaner than the 777. That and a 200 gr Shockwave. I threw a Simmons 3-9 on it and had it shooting good at 100 yards a few shots later. Took it out yesterday morning hoping for a shot and....never saw a deer. Was skunked Saturday morning also when I went out with my bow. This is my first October hunting and I can't say as I'm liking it. Not seeing many deer at all....
Depending on how well your new (to you) rifle patterned with the bullet and powder combo you chose, I would recommend trying out a few different combinations to see what your rifle likes the most. I have a .50 cal CVA Optima pro that will not let me put a sabot in it. They are either all too small and fall straight down the barrel, or are so large they cannot get past the muzzle. I tried several combos of powder pellets and the CVA powerbelt bullets, and settled on 100 grains (2 pellets) of 777 and the 295 grain powerbelt aerotip. If I go down to the 245 grain powerbelts my gun is a pie plate pattern compared to damn near MOA at 100 yards.
Since I bought it so close to the weekend I didn't have time to really experiment much. That's why I was surprised to see it shoot so well at 100 yards with what I'd chosen. The choice wasn't random, but based on internet research over a couple of days. Maybe I got lucky. The 200 grain Shockwave with the sabot is a little tight at first but seems to be working well. I'm trying to get over the feeling that I need to clean a lot better between shots, since I have the screw off breech plug it's easy to take it off and look down the barrel. Not use to seeing all that in a rifle barrel...