Shooting prone 50-100yds isn't very specific but lets see if we can help. Depends entirely on what you want to do and how accurate you want to pay for, that's right I said how accurate you want to pay, and pay you will for accurate ammo. Real potential and real accuracy will not come from a bulk box, if that is all the accuracy you need then try Federal Auto Match. It is the most accurate bulk I ever tried out to 100yds. You are gonna run into real accuracy problems using high velocity stuff at 100yds. Don't try to get faster and faster ammo, it defeats the purpose and still can't defeat the transonic turbulence.that happens between 70-85yds. Many have tried and many have failed.
For the most accurate ammo you can get try the stuff listed around 1050-1080fps, that is the bread and butter for a 22lr, even out past 200yds believe it or not. This ammo is usually pricey so get ready to pay. RWS(which includes Federal 922A and Ultramatch), Eley(not necessarily Sport),Lapua(which includes Wolf,SK,and of course Lapua, POlar Biathlon is a whole nother animal and will only give you results under about 50-55degrees).
Expect to get what you pay for, but just because it is expensive doesn't mean your gun will automatically like the stuff. What is sure is they don't live up to their potential with cheap ammo.