RE: 45 ACP Bullets
well that depends on the size of your barrel. i believe barrels are supposed to be .452 so a jacketed bullet with a diameter of .452 would be the best, now if you are shooting cast bullets then .453-.454 would be best as a general rule for cast bullets is .001-.002 over barrel diameter is best. slugging your barrel would tell you what diameter is best (slugging is the process of taking a slighlty oversized chunk of lead and pushing it down the barrel so that when it comes out the other side you can measure it and determine barrel diameter). Of course just as easy would be to shoot some .451 bullets and some .452 bullets and determine which ones shoot better in your gun. and come to think of it ive never heard of bullets sold at .451, then again i dont load the 45ACP.