Send it back
If you take it to a smith he will have to:
remove the barrel
set back the barrel shoulder
reinstall the barrel
index the barrel
recut the forcing cone
test fire
That comes to about $175-$200.
Cimmaron screwed it up, make them fix it. Note that it may take quite a while, especially if it has to go back to Italy (it would probably be cheaper fot hem to just send you a new revolver)!!