Where could you find a manual or repair manual for the crosman revelation repeater BB rifle?

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.