I also own a 19-3 blued with the 6" barrel of 1969 vintage. Love it!!! $450 sounds like a great deal on the nickel 4 inch barrel assuming the gun checks out ok.
Here is a good read in regards to the possible issues with the forcing cone due to using hotter light bullet weight loads.
http://www.gunblast.com/Butch_MagnumLoads.htm
Here is a good read in regards to the possible issues with the forcing cone due to using hotter light bullet weight loads.
http://www.gunblast.com/Butch_MagnumLoads.htm