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 widly regarded as fundamental to improved accuracy. A few thousandths of an inch change between the bullet & the rifling can make the difference between just-so accuracy & real tack-driver performance. The Lock 'n' load Overall length gauge is universally acclaimed as the most accurate, easy to use & reliable method of obtaining that critical relationship.
To use the OAL gauge, you will need to purchase a modified case to fit your firearm's chamber & thread it on to the gauge. Hornaday offers interchangeable modified cases in all common sizes from .17 Rem up to & including .45-70 Govt. These specially designed prepared cases are threaded at the case head & have a .002 oversized neck to accept the same bullets as you intend to load. This is critical, as the Lock 'n' load OAL gauge dimensions obtained will be accurate to .001". Results such as this cannot be obtained with competative products, which use a simulated bullet with an arbitrary shape.