You can locate a schematic at http://www.remington.com/pdfs/om/om_11001187.pdf.
See related links I put a pointer to e-gunparts.com for the model 16, the have many schematics there as well as the parts page online.
A darn good site. http://www.urban-armory.com/diagrams/rem514.htm
on classic fire arms llc
I am not sure about the diagram,but I would check at numrich gun parts corp. first for the parts you need.
The model 31 was made from 31-49 so the barrel is date codes stamped, I add related links which has a page on the Remington Society of America with a diagram and the table.
Check Remington Society of America Service/Link page: http://remingtonsociety.com/rsa/service
You can find a parts diagram on the CROSMAN homepage. Click on "Download a manual" (at the bottom of the page ) There you will find an owners manual and parts diagram for the model 66. Parts are still available through Crosman. See the related link.
You can go the the Remington website and put in a request for a manual. For some reason they mail you scanned copies rather than make them available online, so you have to wait a couple of days. Numrich (www.e-gunparts.com) has some diagrams online and some for sale.
Numrich gun parts corp.may have a exploded view of this model on there web site.
Send me an email. I have a few parts. Triggers, bolts magazines, and barrels. Papawlambert@starband.net
You can contact Remington directly to see if they have any parts supply left for the model 1148,or you can attend gunshows,look on the internet,pawn shops,etc.