Rem, Fed., Win. all have their own powder loads and are often a mixture of powders. Good luck gettin any of that info from them. From what I have gathered the powders that they are using are not available to the public. Myself I don't mind handloading and do for several rifles. However I try and find a factory load that shoots first. As most reloaders don't want to admit, velocities from fac ammo is hard to duplicate staying within safe presures. At times greater accuracy can be obtained by handloading without the vel. and imho is better. I will take accuracy over speed anytime. Having said this I will shoot fac. as long as I get the accuracy and bullet I want. I load for my 300rum for I want to shhot the 200AB, and also load for my 6mm, 7mmrum and 300rem saum. I am shooting fac from my 7mag, 270wsm,280,25-06 and 22-250. Since this is the TC board I will also state that the 280, 25-06 and 22-250 are all prohunter barrels. the 7mag(160fed AB), 270wsm(140fed AB) 280(140 fed Fusion), and 25-05(120 fed. Fusion) will all shoot 1 1/2'' or less at 300yrds. The 22-250 shooting rem 50 accutip stays under 2 at 300. With these results, I see no need to try and handload. Others will disagree because all they shoot are handloads and would not shoot fac to save em. To each his own.
Dogfox, I believe it would be worth your time to try the fed, Fusion ammo. You didn't state what or if this rifle will be used for hunting. I have really been impressed with this ammo on WT.
You also have the choice between 150, 165, and 180 gr. bullets.
Good luck, DM