I can send you an explded view of a J.C. Higgins M50 which is basically a less expensive version of your rifle. The main differences would be the trigger and bol release. I have several rifles in the .50 and other than a different stock, barrel shape etc., they're the same gun without frills.
http://www.histandard.info/manuals/s.../1083D150R.pdf
If the link doesn't work, I can copy it and mail you the copy. Can't help you on th DOM.
Paul B.