As far as I know the Python's were all made in 357 mag. The Diamonback's were available in 38 spl and 22LR.The Diamondback was a smaller frame (D frame) revolver with the vented rib just like the Python's have.Pythons are a "I" frame if I remember correctly.Allot of people confused them with the bigger snake. I had a couple of the 22's and one 38spl.I still have a brand new Diamondback 6" blue 22. It still has the yellow tag on it.I worked for a gun shop when Diamondback's and Python's were easy to come by.Granted the Python's are a nice gun. I personally I wouldn't put that kind of money into one that isn't NIB.The GS I worked for which was years ago was a Colt Distributor. I saw some Python's with issues right out of the box. There was a few that came right from Colt that were out of time.I had one for a very short time trading it for a nice Sako rifle.If you decide to buy it I'd go over it with a fine tooth comb for that price.
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On second thought.
Faintly I do seem to remember now seeing or hearing about a Python in 38 spl.I really can't recall it but it is starting to sound familiar.Sorry if I was wrong.