When I was shooting SB silhouette with my dad, we used to shoot Winchester T-22's. They used to shoot very well, but after some time, it seemed that the quality went downhill, and the accuracy wasn't consistently there. When Federal came out with the Gold Medal Match, it cut group sizes at 100yds in half in his 40x, with none of the fliers T-22's seemed to have. It was so expensive he saved it for matches, and continued to practice with the Winchester's. Now that the Federal is no longer available, If I am serious about group size I now use Wolf MT, as it has been consistently the most accurate in my rifles. I mostly shoot the Federal value packs though, much cheaper, and decently accurate in all of my guns.
At our height, my dad and I burned through roughly 2 cases of 22 ammo every year, then SB silhouette slowly dwindled to very few matches, and our shooting slowed considerably. He still has a full smallbore silhoutte range he built on his property, and we still shoot, but not nearly as often as we once did. I don't think I have ever beat him. Billy