Valad,
As you probably know its tough to find anything right now, but the bullets I've been seeing in my part of the world consistently are the Hornady XTP's. I've got a good load worked up for one of my 444's using that bullet, but I prefer the Speer 300 grain Uni Cor. They have been impossible to find anywhere, but I laid in a supply a few years ago so I just sit on what I have and use them sparingly.
If you don't drive them at top velocities the 240 grain flavors will work fine for deer and they can be found in my area. I laid in a bunch for my 44 mags.
I hope you find components during this crazy time because you sure received a fine rifle.
Best powders for me are Re 7, H 322, and H 4198. Good luck!!
