Hornady Lock-N-Load Over All Length Gauge - Straight. A good "jump" (the distance between the bullet's ogive and the point where it touches the rifling) is necessary for pinpoint accuracy and this Hornady reloading tool allows you to determine the precise seating depth of your rounds for optimum jump. Hornady has designed the Hornady OAL Straight Bullet Seating Gauge to use specially made modified cases which are threaded at the case-head. This modified casing design was the only way Hornady could achieve the stellar .001" accuracy variable on the reloading equipment. The straight edition of the Hornady OAL Gauge is designed for bolt action and single-shot firearms and it's the most precise version of the tool. To get utterly accurate bullet seating measurements for a highly accurate round use the Hornady Lock-N-Load Straight O.A.L. Gauge. Specifications for Hornady LNL Bullet Seating Gauge: Weapon Types: Bolt action single shot straight-line chamber access firearms Features of Hornady Straight Seating Gauge: Determines proper seating depth with an accuracy of up to .001" Straight design for ease of use Uses Hornady Modified Casings Designed for all bolt action and single shot firearms plus weapons with straight line chamber access Package Contents: Hornady Lock-N-Load OAL Straight Gauge C1000 Hornady Straight Model Lock-N-Load Over All Length Gauge