Try e-gunparts.com
@ 4"
I would start my search at Smith and Wesson first.
Your smith and Wesson model 686 is valued at 250-425 dollars depending on condition.
What is the value of a model 24 Smith & Wesson revolver with a 4" barel? It has never been fired.
Yes.
You will need to ask a gunsmith
22LR
4.5 or 6 inches
The best that I can do is say that the smith and wesson model 28-2 was made by smith and wesson from 1961-1969.
Look on frame inside the cylinder area to find the model number of a Smith and Wesson 357 mag snub 2 in stainless barrel
Model 37