I don't know how well they would shoot for you, but another option with the .54 1:32 twist would be Speer 400 grain soft point flat nose bullets in 54/45 sabots. You should be able to get those up to a velocity to easily reach the energy requirement (1600 fps would do it) and have a tougher bullet than the lead Hornady.

http://www.speer-bullets.com/ballist...il.aspx?id=126