threading alignment tool (TAT), otherwise referred to as a die starter for caliber rifles and 1/2"x28 TPI dies. The purpose of this tool is to squarely guide the die onto the barrel of the gun, eliminating the chance of crooked threading so you can attach muzzle brakes, flash hiders and other barrel mounted attachments requiring this pitch thread with ease. These TATs are approximately 1.5" long, the threaded portion is 1/2", the bore side is 1" long and is slightly under your choosed caliber (as it is not uncommon to see bores that vary in size). (the purpose of this tool is ONLY to align the die at a perfect 90 degrees to the barrel)