Hornady Lock-N-Load Overall Length Gauge for Bolt Action Rifles

The Hornady Lock-N-Load Overall Length Gauge for bolt-action rifles is a must-have reloading tool for anyone building ammunition that needs to fit perfectly in their chamber. Finding the correct overall length (OAL) for your specific rifle and bullet combination is one of the most critical steps in handloading—too long and it won't chamber; too short and you lose accuracy and velocity. This gauge takes the guesswork out of that process in just a few minutes, giving you the precise measurement you need to load safe, accurate ammunition.

Here's how it works: you thread a specially modified cartridge case onto the tool, insert your bullet into that case, then insert the whole assembly into your rifle's chamber. Push the rod forward until the bullet contacts the rifling, lock the rod in place, remove the tool, and measure the distance from the base of the case to the tip of the bullet with dial calipers (a bullet comparator makes this step even more precise). Once you know your OAL, you can load all your ammunition to that specification. Want to check a different bullet? Swap it in and repeat the process. This tool is also excellent for checking throat erosion over time and for evaluating the chamber condition of used rifles before you buy.

The straight model is specifically engineered for bolt-action rifles and single-shot rifles—the design you're looking at. Hornady makes over 60 different modified cases to fit various calibers, so you'll find the right one for your cartridge. This is the kind of tool that pays for itself the first time it helps you avoid a dangerous reload or improve your group size by getting your seating depth exactly right.

Key Features

• Designed specifically for bolt-action and single-shot rifles
• Simple, repeatable process for measuring overall length in your specific chamber
• Uses industry-standard modified cartridge cases (over 60 different calibers available)
• Straight design optimized for non-autoloading actions
• Works with any dial calipers and is compatible with bullet comparators
• Also useful for detecting throat erosion and evaluating used rifle chamber condition

Frequently Asked Questions

Which rifles does the Hornady Lock-N-Load OAL Gauge work with?

This straight model is designed specifically for bolt-action rifles and single-shot rifles. A curved model is available for semi-automatic and lever-action rifles. Both models use the same modified cases, and either tool will work on AR-15 platform rifles.

What modified cases do I need for my caliber?

Hornady manufactures over 60 different modified cases to fit various calibers. You'll need to verify that a case is available for your specific cartridge before purchasing this tool.

Do I need special equipment to use this gauge?

You'll need a set of dial calipers to measure the final OAL. Hornady recommends using a bullet comparator at the same time for the most accurate measurement, though it's not required.

Can I use this to check my rifle's condition?

Yes. This tool is excellent for periodically checking throat erosion in your barrel over time, and it's a quick way to evaluate the chamber condition of a used rifle before purchase.