It's a prop. Looks good but none functional. The base for the copy is going to be some PVC drainpipe from B&Q:
Being up for a challenge I agreed and after playing with Creo Elements for a few hours I came up with this:
It is a combination of PVC drainpipe, Maplin project box and 3D printed parts, the hand grip being from my existing gun models.
I started printing the the first parts today, but after an hour or so I was met with this:
The X axis was completely jammed. I had to undo the idler bearing to allow me to move it:
The problem was caused by the pulley on the X axis stepper motor slipping along the motor shaft, so far that it jammed the motor:
Unfortunately I had to disassemble the motor bracket as the pulley had stopped with the grub screw in a position that was inaccessible. I managed to fix it in about an hour and I'm re-printing the parts. If successful, this will be a kit at Tagbits.