Friend of mine passed away bout 1 year ago. His girl friend gave me his old Sheridan air rifle. Trying to find out what model it is, and if it is fixable. I'm thinking he bought it between 1965 and 75. The only markings I can find are on the right side of the receiver just below the bolt. Says Sheridan Products Inc, and below that, Racing Wisc USA. Hold Down to Fire on tang. Iron sights. Cap on end of tube is a grey color if that means anything. Rifle does not pump up. Suspect seals of some kind? Do it yourself job? Came with 3 yellow boxes of Sheridan 5mm pellets 500 rnds each, so I'm guessing that is the caliber. Does not state caliber anywhere on the gun that I can see. Thanks for any info...Bill