You can find out how old an HS Model 10 22 revolver is by taking it to a local pawn shop or gun dealer. You can also use publications that are written to help identify the age of a revolver.
That 22 revolver is IJ targeted sealed made in Pittsburg, Ms.
The year a HS model 10 22 revolver was made should be stamped on the metal below the barrel on the left hand side of the gun. This will be a bit ahead of where the grip begins.
You can find a 22 mag cylinder for a 22 mag revolver mod 21S MIW Germany on eBay. You may also be able to find one through antique sales and antique gun collectors.
@ 75 years old
Call Colt
Ruger website, customer service, historical data, revolver, single six, find your serial number.
http://www.gunpartscorp.com/forum/
Pre 68
You must call Colt to find out.
Blue Book of Gun Values
IF the revolver is marked ".22 LR" yes. If it is marked ".22 WMR" or .22 Mag" or " .22 WRF", then NO.
50-100 USD This price really just depends where you are. A 22 mag revolver for 100 bucks.....ya, I don't know where you would find one. The cheapest your going to find a revolver of this style in the NW is around 300 plus. A little less for a LR 22 revolver. You can also check a few of the online gun auction sites to get a better idea of the value........All that said, if you want to sell it for 50-100 bucks, I'll buy it.