First, took a chance a number of years ago and bought a 7.62x25mm Tokarev CZ52 complete with original holster, extra magazine, cleaning tool and lanyard from an on-line Montana Estate sale. Online ad showed only a single B/W photo of an open cardboard box with all pieces included strewn about somewhat haphazardly. All the pieces appeared to be there when I looked, just were not very well organized. Auction had about a week left and I was later somewhat surprised that no-one had bid on it yet with less than a day left. Won it later with a single bid... right place, right time! I'd done all my research on this model prior to this and knew that it was originally designed to fire 9x19mm Luger rounds.
The Soviets intervened and dictated it be changed to fire their 7.62x25mm Tokarev round. My interest was really its roller-delayed recoil system, but used in a pistol. This action is also found in the German WW2 MG-37/42 machine guns... very intriguing! My CZ52 had evidently been very little used during its 1954-77 'Soviet life' before being shipped here for sale as surplus, ...perhaps even un-issued! When I talked with the lister after the sale, he indicated that he'd found it on a top shelf in the bedroom closet while clearing out the house. It was still in its original cardboard box and evidently forgotten during the original owner's lifetime.
The CZ52 did have a few quirks and seemed to like original magazines (4 spot welds) better than the newer ones with five I bought later. I was a bit surprised somewhat later to learn that this gun was completely assembled using only 'staked pins' and ONE single nut and bolt! My CZ52 also exhibited quite a bit of slop in the slide-release (take-down latch), so I had my gun guru make a new one that fit a bit more tightly. I owned quite a bit of surplus S&B 9x19mm ammo in those cute, tight little green 5x5 boxes purchased years ago when it was still just a few pennies a shot.
A few months later I found an aftermarket CZ52 9mm 'ported sports barrel and spring' for sale and bought it as well. Put both the "sports" and Tokarev barrels through their paces a bit and then discovered '9x23WIN' ammo! Was impressed by its stats and started thinking about perhaps converting my new 'sports barrel' to 9x23WIN! Went back and forth on this for a while to be honest however, but finally decided to go ahead with the 'WIN' conversion. Figured out it was a relatively easy job for any Gun Smith with a proper 9mm 'case reamer' to ream the existing '9x19 case' chamber to '9x23WIN case' size.
Quite simple to do by reaming the barrel an additional 4mm (0.164") for WIN-case length and massaging the barrel entry ramp a bit to smooth out the WIN bullet's somewhat steeper magazine exit radius. Must say I'm pretty pleased with the feed and firing of the two 9x23WIN ammo types I've tried so far in my converted CZ52's 'sport-barrel'!

