I frequently handled a pristine .32 ACP version about two years ago in Iraq. An interesting little weapon (for its size) in that caliber. We were unable to fire it despite several months of trying (unsuccessfully) to locate .32 fodder. God knows how it wound up in Iraqi hands, but sooner or later you run across examples of just about everything in Iraqi arms rooms.
I fired a .45 ACP version back in 1983. One example of this weapon was still on the property book for a particular unit at that time. Mostly regarded as a range toy and novelty. It was a good deal larger than the 9mm & .32 versions.
Popular wisdom has the Welrod never fielded in .45 ACP...but the unmarked model I fired was most certainly in that caliber.
It was an extremely quiet suppressed weapon. At that time, I was more used to open bolt suppressed SMGs (Uzi, MP5-SD, M3A1, MAC-10/11, Walther MPK, etc.). The Welrod was significantly more quiet with the only noticeable noise being the smack of rounds into targets and backstop.
Despite being used to several different types of supressed weapons, I truly thought my first shot from the Welrod was a misfire and ejected that "dud" round to get another ready to fire. I then noticed a slightly smoking and expended .45 ACP brass case at my feet. Spooky quiet.
As previously mentioned, a very specialized weapon for point blank dispatch of people or animals (and providing little ability to quickly deliver a followup shot). One for the history books, but not especially practical.
I wasn't aware of anyone making a modern reproduction?