This paper deals with the measurement of spherical impactor positions, velocities and acceleration (translations and rotations) during medium velocity impact experiments performed with gas-gun devices. A dedicated 2D Digital Image Correlation (DIC) technique based on customized interpolation functions is presented. The proposed method considers the rotations of the projectile which a standard subset-based DIC technique would undoubtedly have difficulty managing. Emphasis is placed on metrological performance and various validations are proposed. Measurements are additionally compared to those retrieved with conventional techniques. This DIC method provides a precise quantification of projectile motion and impact loads during gas-gun tests with a single high speed camera.