The Lee Collet Neck Sizer Die comes in a wide variety of sizes to accommodate all of the most popular cartridge case calibers. This neck sizer die squeezes your case necks against a precision mandrel to provide ideal bullet fit with little to no runout. If you are looking for a neck sizer die that ensures maximum accuracy you need one that seats the bullet out far enough that it touches or almost touches the rifling. This is what the Lee Collet Neck Sizer Die guarantees and it provides you with the ideal shot start pressure that you would normally only get from the crimp.