Ok, so when I ask about the diameter of a bullet, I am told "go read your manual." So let me ask this, Where in the manual does it tell you? Example, in "Modern Reloading" in the 45 ACP part, there is a diagram of the round. the diameter for the bullet shows .452, this is not separate for lead bullets, following is frangable, jacketed and lead. In the Hornady 8th edition, it says the diameter is .451. Now, unless I am wrong, we use .451 for jacketed bullets, and .452 for lead bullets. Correct? Reason I am asking is because I am wanting to order some dirty thirty bullets, and because of this issue I want to be sure before I order. I am seeing in both books .308. Is this correct? And if so, it seems there are several rounds that use this diameter. So, can bullets used in a 30-30 be used in a....303 Savage, 300 savage, 308 Winchester, etc.? Is there anything else that needs to be looked at while determining which bullet to get? Enlighten an older youngster!!