I’ve always been a fan of the Fitz Special concept, although not a practicing fan. More of an idle curiosity you could say, as I personally think they are unsafe.
Around 1926, retired NYPD cop John Henry Fitzgerald began customizing both full-sized Colt New Service, Police Positive, and Police Positive Special models to make them small concealed handguns, much like Colt’s then-new Detective Special. This modification included shortening the barrel to two inches or less, fitting a new front sight, removing the hammer spur and carefully checkering the top of the now-bobbed hammer, shortening the grip, and—unique to this type—cutting away the front 1/3 of the trigger guard and rounding off the now open edges.
This trigger guard surgery left the bulk of the hammer exposed while carefully shrouding the very bottom and back of it to avoid snagging in the pocket. The open trigger guard allowed faster firing, accommodated large or gloved fingers, and according to some accounts made the weapon easier to fire through a pocket (if needed). While these modifications were done to large frame revolvers, they were performed mainly to the smaller Colt Detectives.
Although Fitz only converted less than 200 Colts, (some say as few as 20), the concept lived on and you see many other guns converted to the same degree.
Like this M1917 .45ACP moon gun:
My friend Ian over at Forgotten Weapons got a chance to check out a Colt Fitz at RIAC last week: