Most firearms manufacturers will provide you with copies of the owner's manuals for their firearms at no charge, if requested. Many provide them on-line. Another resource for firearms manuals, especially for the obscure ones, is a website run by Steve Ricciardelli of Sant Marie, Montana. Stevespages.com has hundreds of manuals in PDF format to download. Click the link and check them out. The manuals are free, but Steve requests donations to offset costs.
Steve's site also has separate firearms and related equipment parts breakdowns, U. S. Army field manuals, archival books about firearms and reloading, and other interesting material. Check out the index of information here.