The Redding 300 Remington Short Action Ultra Magnum (SAUM) Instant Indicator is a precision made tool that allows a hand loader to quickly compare headspace and bullet seating depth within .001". The Instant Indicator leprovides an extremely quick method for comparing bullets, seating depths, fired cases, sized cases, trim lengths and loaded ammunition for uniformity. Easily perform any of the following tasks: Sort bullets for uniformity Sort cases fired in two or more rifles Sort sized cases for uniformity Set up sizing die correctly Compare sized cases to fired cases to determine the amount of headspace Check uniformity of shoulder bump C Mfg: Redding