I've found various YouTube videos helpful for field stripping Remington 870 shotguns and reassembling them when no book was available. Perhaps others here have found useful how-to videos for caring for their guns when a manual can't be obtained. I purchased my 870 pump secondhand and the seller provided no book. This gun is not intuitive to field strip as are Mossberg pumps I have owned. The two shell catches are tricky and have to be pressed in a certain order to get the slide and bolt in and out of the receiver.