Not sure what parts you need butwww.midwayusa.com has some parts and e-gunparts.com also has them from time to time. also try gunbroker.com and looking the parts section, you may find parts or a parts gun with what you need.
Parts of Savage Springfield Model 18 are available at Gun Parts Corporation. These can also be bought from Field and Stream.
Numrich.com
check the website at gunpartscorp
Try Savage model 94
Bobs gun parts
gunpartscorp.com seems to have everything you have to check your model number but most of the parts seem to there
Try Numrich Gun Parts, I belive they have parts for them.
Check www.e-gunparts.com
gunbroker.com
I seem some parts for your gun on e-bay
Your gun is a Savage model 620. Try gunpartscorp.com for parts.
Hello: Your best bet is to watch the gun auction websites for parts or non-working parts rifles that have the parts you need. Be aware that Savage made several variations of the Model 3. And parts between the variations don't always interchange. Savage also market Model 3 variants under the Stevens and Springfield maker name (both owned by Savage). It took me 2 years to find bolt parts for my early Model 3.