what do you consider a heavy conical? I have a friend with a TC hawken .54 that shoots consistent 3 inch groups at 100 yards with a 430 maxi ball, I have a .54 TC greyhawk that shoots about the same size groups with the same maxiball, both with open sites and I'm sure they would do a little better with a scope. I also have a Cabelas hawken that will hold about a 4 inch group with the same bullet. All are 1-48 twist I believe.