Try e-gunparts.com
The Revelation Model 150 is a Marlin model 49: See; http://www.e-gunparts.com/productschem.asp?chrMasterModel=082Zz49+RIFLE MARLIN 49 RIFLE Barrel, .22 Cal., 22", Used, Stamped Revelation 150
go to e-gun part
Revelation was a "store" brand used by Western Auto for guns sold by them, but made by others- usually Savage, Marlin and Mossberg. Find the model number from your rifle, and go to the website for gunpartscorp. Under the "company forum", on the left side, scroll down to "cross reference". Find the model number under Western Auto, and see what the original make and model was. Then contact that company, and request a manual.
Try e-gunparts.com
Numrich Arms is a good source for gun parts.
Yes! Crosman made all the BB Guns/Rifles for Western Auto under the Revelation brand name. (Unfortunately you did not state the model number so I can't tell you exactly which Crosman model it relates to.) So here is a suggestion. Crosman has Most all their manuals online you will have to go through all of them to find your model. See the link below.
Try gun shows.
Take it to a gun smith.
Contact Colt, on line aucitons.
Go to ( See the link below ) and find your parts and owners manual for your gun or rifle. Crosman keeps a web page for older airguns.
Gun shows, gun shop