Hornady Rimfire Thickness Gauge allows shooters to sort their ammo by rim thickness. Sorting ammo by thickness has been proven to aid accuracy. The gauge attaches to the blade of a 6 inch caliper and includes bushings to use for all .17 and .22 caliber rimfire ammo including the new 17 HMR, HM2, and 22 Magnum ammo. Easy to use and enables you to sort through ammo quickly.
Sinclair, Issue:5B, Page:124