I thought I`d have a crack at one of these after I`d been reading a website on the SOE.
The only pistol I had was my trusty KWC 1911 springer. It took less time than I thought (about 20 minutes, bar the paint on the outer tube).
I had some 10mm od ali tube which is a nice interference fit in the front recess of the 1911. I drilled some holes through the tube at 20m intervals, popped a 3/4" rubber tap washer on each end, wrapped some sliced up foam pipe lagging around it, and shoved it all in a 3/4" steel tube. All was superglued together.
I was surprised at the difference it makes to the noise, shooting the gun normally gives a 'clack sound', with the silencer fitted there is a noise best described as an audible bottom fluff (as opposed to the more common rasping fart).
Unfortunately I didn`t take any pics of the thing in bits as I thought it was going to turn out as a bag of shite, but I was pleasantly surprised with the outcome.
All the bits came from B&Q, the outer tube is the thin wall chrome stuff that is made to hold up worktops. 
the high standard hdm i made from a kj works ruger mk1 benifited muchly from the home made silencer. need to glue the baffles in next time though as it blew them out the end lol. All my bits were B&Q or stuff i had lying around. its dead easy to do. just a shame there werent more silenced guns
