They can be used with .22LR – .22WMR & .17MH2 calibers. The Tuffer Buffer is made with the very best virgin materials available on the market today. They’re precision made to fine tolerances, have high cut & tear resistance, oil and solvent resistance, abrasion resistant, have superior load bearing properties, great high impact resistance and good low temperature flexibility. They are also non corrosive, fit directly into your 10/22 receiver and will most likely BE THE LAST buffer you buy for your rifle.