Private Snuffy Smith

Private Snuffy Smith is a 1942 American film directed by Edward F. Cline and starring Bud Duncan as Snuffy Smith.

The clever Don Elbie has invented a new rangefinder that he hopes to have adopted by the army. General Rosewater hopes to test the new rangefinder in war games with a rival general. A pair of Fifth columnists hope to steal the rangefinder but are defeated by Snuffys wife Lowizie, Snuffys invisible dog and his hillbilly neighbours.

Source: Wikipedia