Hornady headspace bushing 375. Designed for use in the Lock-N-Load Headspace Gauge, these bushings are machined to exacting tolerances to ensure reliable results every time you use them. The Lock-N-Load Headspace Gauge allows the reloader to precisely measure cases while sizing them for a perfect fit in any firearm. This bushing fits 6mm Rem, 257 Rob, 25/06 Rem, 270 Win, 7x57mm, 280 Rem, 30-30 Win, 20/06 Sprgfld, 300 H&H, 7.62x39 Br, 6.55x55 Mauser, 7mm WSM, and 30-40 Krag.