My son played around with conicals in his rifle over the summer.
First was the Great Plains bullet. They seemed to shoot well with any charge. Though he didn't shoot at 100 yards, he had no problem printing 1 1/2" groups a 50 yards. We wanted to dismiss that bullet, however, because we prefer to cast.
Next we tried the Lee REAL bullet. I don't recall the weight, but it was the heavier of the two. On top of the powder, it was all over the place. Using overpowder wads it settled in pretty easily. I don't remember if he was able match the accuracy of the Great Plains, but he was able to tighten it up significantly with the addition of the wads.
At 15 years old both bullets turned out to be a bit much for him, and we didn't take it any further.
I'm still tempted to toy with the idea myself, but I'm not sure with all the metal hardware in my shoulder that I'll want to do so either. They thump pretty good on both ends.