Picked this up on Ebay. I believe it's from around 1967-68. The same time my parents bought me a Crosman 760 for Christmas. Gun is in pretty good shape. Stock was refreshed which is kind of a bummer. Almost rust free and was totally restored internally. Downloaded the original user manual that states up to 10 pumps. At 10 pumps, the manual stated 85% of the guns power potential would be achieved. I read in some other airgun discussion forum that the gun could be pumped up to 20 times. My manual says that minimal gains are achieved by over pumping the gun. I shot it 5 times over my chrony today with BB's. Four times at 10 pumps for an average of 605fps. Low of 600 and a high of 609. Shot one shot with 5 pumps and got 492fps. What can all you knowledgeable AGN geeks tell me about this rifle ? There is no serial number on the reciever.