Hornady Lock-n-Load Curved OAL Gauge. A.L. Gauge C1550 is universally acclaimed as the most accurate easy-to-use and reliable method of obtaining that critical bullet seating depth. To use the Hornady reloading tool you will need to purchase a Modified Case to fit your firearm s chamber and thread it onto the gauge. Once you use the Hornady Curved OAL Bullet Seating Gauge you will be able to regulate seating depth and the resulting jump to the rifling widely regarded as fundamental to improved accuracy. The reloading tool is built for all autoloader lever-action or pump-action rifles and it also fits all bolt-action and single-shot firearms. Hornady has designed the gauge to insert easily into chamber through your firearm's ejection port. Earn pin-point accuracy through perfect bullet seating when you use the Hornady Curved OAL Reloading Gauge. Hornady Modified Cases are REQUIRED for proper use of the OAL Gauge Specifications for Hornady Lock-n-Load Curved OAL Guage: Manufacturer: Hornady Quantity: 1 Weight: 0.22 lb Color: Red/Silver Condition: New Features of Hornady O. A. L. Curved Gauge: Curved O.A.L. gauge by Hornady Helps regulate seating depth for a more accurate shot Curved model inserts into chamber through ejection port Works with all auto-lever lever action pump action bolt action and single shot firearms REQUIRES purchase of a Modified Case to fit your chamber Package Contents: Hornady Lock-n-Load Curved OAL Gauge Hornady C1550: Lock-n-Load Curved OAL Gauge