A popular designation for the 230-grain full metal jacketed round-nosed military load for the .45 ACP. By extension, loads using similar bullets in the other auto pistol calibers. Hardball, a slang term used for full metal jacket bullet pistol ammunition, particularly in .45 ACP caliber. The full metal jacket (FMJ) or full metal case (FMC) bullet is also known as "hardball." The FMJ is almost entirely encased in a jacket of a reasonably malleable metal (usually copper) harder than the bullet's core (which is usually composed of soft lead).