Looks like a reasonably good job by a gunsmith that knew what he was doing and not just a bubba hack job. The mass of the barrel should help tame the recoil. More photos would be appreciated to see the frame modification, how the bolt face was opened up, heavier springs, etc. I have seen a photos of a couple of .45 conversions that were made with standard Luger frames (not enlarged as John Martz does by splicing two frames together). I would imagine they might have feeding problems because of the different overall length of the 9mm vs .45 cartridges. Perhaps the custom made magazine and frame modification accommodates this.
I suspect it is probably functional and could be fired (but I assume no liability if you do!
). Is there any evidence that it has been fired?
Neat gun. Looking forward to some more photos.