I believe the 4506-1 shares the same frame with S&W 10mm's. Is it possible, and if so safe, to change slide / barrel assemblies and have a 10mm option in a 4506-1?
There are several differant machining operations used on the frames that don't allow easy conversion. The mags don't readily exchange between the two. But anything can be done, it all comes down to who's writing the check.