Try e-gunparts.com
You can find Sterling trucks for sale using the dealer locator on the official Sterling Trucks website. You can also find them from personal sellers on the auto section of the eBay website.
Buyers can find a Sterling BMW for sale from a number of auto retailers. This vehicle can be purchased from Auto Trader, eBay Motors, AOL Autos and from BMW Buyer.
Recommend you find a good gunsmith.
You can find out at Proofhouse.com in the Colt tables.
Send me your email & I'll send you a scan of the manual.
Your best bet is to find a gunsmith and ask for help.
you should be able to find browning firearms on the web with no trouble.
Sterling Arms Corp of Gasport NY made the Model 283 Target 300 pistol in 1970-71. The 300L (light barrel) was made the same years.
If you don't have a manual, find a gunsmith and ask for help.
You will have to call Colt to find out.
Please refer to the link below and choose the manual for the High Power pistol. There you will find instructions for disassembly and cleaning: http://www.browning.com/customerservice/ownersmanuals/index.asp
it is disassembled the same way as a military 45 pistol..................