Hornady

One of the best kept secrets in accurate reloading is precise bullet seating depth. Regulating seating depth and the resulting jump to the rifling is widely regarded as fundamental to improved accuracy. A few thousandths of an inch change between the bullet and the rifling can make the difference between so-so accuracy and real tack-driver performance. The Lock-N-Load O.A.L Gauge is universally acclaimed as the most accurate easy-to-use and reliable method of obtaining that critical relationship. - To use the Lock-N-Load O.A.L Gauge you will need a Modified Case (sold separately) to fit your firearm's chamber and thread it onto the gauge. Hornady offers interchangeable modified cases in most common sizes from .17 Remington up to and including 500 Nitro. These specially prepared modified cases are threaded at the case-head and have a .002 oversized neck to accept the same bullets you intend to load. This is critical as the Lock-N-Load O.A.L Gauge dimensions obtained will be accurate to .001 These results cannot be attained with competitive products which use a simulated bullet with an arbitrary shape. - For all bolt-action and single-shot firearms or any firearm with straight-line access to the chamber. This model is preferred as it is most precise and user friendly.