RCBS 13665 Case Trim Die 7mm Remington Magnum Doubles as a visual case length gauge. Run a case into the trim die and if the case sticks out above the top of the die, it's too long. File the case down until it is flush with the top of the die. Precision machined sizer die chamber with slightly larger neck to ensure accuracy in gauging case lengths. Heat treated to withstand a file bearing against the top surface without damage to die.