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It's possible a good pistolsmith might be able to re-thread and fit a Diamondback barrel, BUT.... You better find a REALLY good pistolsmith.
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Just to amplify a bit, even the very best smith couldn't make it work as it sits. In order to fit a threaded barrel to a new thread pattern, the minor diameter of the existing barrel thread must be equal to or greater than the major diameter of the new barrel thread. In this case, it's not even close.
The reason is that the barrel threads need to be machined off, and new threads cut. To machine off a thread in the 32-36tpi range, you need to take off something in excess of .004" - which, in this example, would leave us at least .003" undersized.
Now, since it's "only" a .22 caliber, it would be theoretically possible to reduce the diameter of the barrel, thread it, then thread on and secure a sleeve - which could then be threaded to match the frame. THEORETICALLY, you understand.
Given the scarcity and value of .22 Diamondback barrels - IF you can find one in good condition - and the value of all Colt .22 revolvers, it's really not a recommended course of action. You'd have a whole pile of money tied up in a gun whose collector value went through the floor when the job was complete.
Just MHO, of course. /forums/images/graemlins/wink.gif