Hornady Lock-N-Load OAL Gauge Straight

Hornady Lock-N-Load O.A.L. Gauge, you will need to purchase a Modified Case to fit your firearm's chamber and thread it onto the Gauge.
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

To use the L-N-L O.A.L. Gauge, you will need to purchase a Modified Case to fit your firearm's chamber and thread it onto the Gauge.
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

If you want to improve the accuracy of your loads you're running through a bolt action rifle, this seems to help in the aspect of determining your over-all length based on your specific rifle, and the brand or style of bullet you are loading. It's easy to use, and a convenient too to have if you are loading for several calibers, or for each time you change to a different brand or style of bullet.