I would start at numrich gun parts corp.they can be found on the web.
Check www.e-gunparts.com
gunbroker.com
Look at triplek.com They are $36.00 for the 1904-1915 model pistol
gunpartscorp.com seems to have everything you have to check your model number but most of the parts seem to there
Try e-gunparts.com
Your gun is a Savage model 620. Try gunpartscorp.com for parts.
You can try WWW.savageparts.comthey handle a large number of parts for savage Stevens arms
Numrich gun parts corp should help.They may be found on the web.
The Sears model 2200 is the same as a Savage Model 80 Series A.
Try gun shows; a gun smith might be able to make one.update:There is no model 1905 Savage automatic pistol. Savage made three production automatic pistols, all in both .32 and .380, the model 1907 (made 1908-1920), the model 1915 (made 1915-1917), and the model 1917 (made 1920-1928). All of these have the date "21 November 1905" (in some form) stamped on th slide. This is the date that Elbert Searle was awarded his patent for the pistol design which was the basis for the Savage automatics, and has no connection to the model or date of manufacture.Over the years, Savage used two versions of the different firing pin in these pistols, but they are interchangable. You can get them from dealers in firearms parts that carry Savage parts (or, of course, always have one made).Two online sources (there are more): as of late 2009 the firing pins are available for about $25 from Numrich(http://www.e-gunparts.com/model_new.asp?CatID=5118) - look under models 1904, 1907, 1908, 1910 and 1917 and for about $20 from Bob's Gun Shop(http://www.gun-parts.com/firingpins) - look under Savage 1904-1907 and Savage 1917. (Yes, the models these dealers list are incorrect -- Numrich's model 1904 and 1908 are actually model 1907s, and their model 1910 includes parts for both the model 1907 and model 1915; Bob's model 1904-1907 is actually a model 1907 and model 1915.)Parts for these pistols are sometimes available on GunBroker and AuctionArms websites.
I have a Model 101-22 Cal. L.R. SN 10467 that I will sell for parts.
Try e-gunparts.com