The Lee Bulge Buster Kit is a simple tool that fixes the bulge often found at the base of pistol brass like .40 S&W and .45 ACP. Used with a Lee Carbide Factory Crimp Die (sold separately), it lets you push the entire case through the die's sizing ring, removing any bulge a standard sizing die might miss. This ensures every reloaded round will feed and chamber reliably in any pistol.