Are you talking about lead conical bullets or lead bullets in sabots?
I'll make my suggestion either way:
For a pure lead conical bullet, I've found the 460gr bullet made by No Excuses shoots better out of my Knight USAK than any other conical I've tried. Shoot these over about 85gr of 2fg777 and hunting accuracy is good and that bullet HAS to be devastating on game. Here is their website: http://muzzleloading-bullets.com/
If you're looking for a saboted lead bullet, then I highly recommend those made by Precision Rifle of Canada http://www.prbullet.com/
Their QT series in 300, 350, & 400gr shoot marvelously and are devastating on game - expanding to double their size.
