If you use European cartridges look for the letters CIP on the box. If they state they are o.k. for 65mm., 67mm., or 70mm, you are o.k. One thing of note that although Proof tested for the 70mm. 2 3/4" cartridges I would avoid heavy loads. Although the gun is now tested safe for them it was made as a lightweight game gun and best used with light cartridges to avoid excessive recoil and punishing an old gun. Game cartridges in the 28 or 30 gram range would be good choices. Lagopus…..