The Hornady Lock-N-Load Rimfire Thickness Gauge (Hornady part no. RF17) attaches to a caliper and lets shooters sort .17 and .22 caliber rimfire ammunition by rim thickness. Sorting ammo this way groups rounds with similar ignition qualities, which competitive shooters and varmint hunters use to squeeze more consistency out of factory rimfire ammunition. The gauge ships with bushings covering most common .17 and .22 rimfire cartridges, though it is not compatible with 17 WSM. For anyone chasing tighter groups from a rimfire rifle without handloading, rim-thickness sorting is one of the most effective low-cost tricks available.

Key Specifications

• Covers .17 and .22 caliber rimfire ammunition, with included bushings for most common chamberings.
• Attaches directly to a caliper for quick, repeatable rim thickness measurements.
• Not compatible with 17 WSM, an important limit to know before buying.

Frequently Asked Questions

Why sort rimfire ammo by rim thickness? Rounds with similar rim thickness tend to share similar ignition qualities, which can tighten groups from a rimfire rifle.

Does this gauge work with 17 WSM? No, Hornady notes it is not compatible with 17 WSM, only standard .17 and .22 rimfire chamberings.

Buy the Hornady Lock-N-Load Rimfire Thickness Gauge

Sort your rimfire ammo like the competition shooters do. Order it from Hornady‘s case preparation lineup, and our Lubbock, Texas team can help it get to you as soon as it’s ready to ship.