The Hornady Lock-n-Load .375 Caliber Bullet Comparator Insert is a precision reloading tool designed to work with the Hornady Lock-n-Load Bullet Comparator for accurate bullet seating depth measurement.Hornady Lock-n-Load .375 Caliber Bullet Comparator InsertMeasures bullet length from ogive for consistent seating depthAttaches to caliper blade with thumbscrew systemEliminates bullet seating depth variationEasy to use with quick caliber changesEssential for precision reloaders seeking consistent ammunition performance this insert enables accurate ogive-to-base measurements for optimal bullet seating in .375 caliber cartridges.