What is the ballistic difference between the .45 long colt and the .45 acp?

45 ACP hardball was designed to come close to duplicating the old round-nose black powder load in 45 Colt. Comes pretty close. Of course, bullet design has come a long way since then (and you certainly don't have to worry about revolver cartridges not feeding well), plus the 45 Colt has tons of extra powder space for smokeless propellants, so it can be really loaded up if your revolver is strong enough, as with a Ruger Blackhawk.