If you ever wanted to fire a VZ52 than you likely hit a dead end while searching for the proper ammunition, rejoice as there has been a solution! The VZ52/57 is a conversion chambered in 7.52x39mm rather than the defunct 7.62x45mm.
Czechoslovakia adopted VZ52 pattern in 1952 and the nation became a Warsaw pact member in 1955. Some, but not all, VZ52 were subsequently converted to take the standard Russian ammunition. The conversion was achieved in a novel manner: the smaller 7.62×39 chamber was pinned within the larger 7.62×45 chamber, the barrel remained original. I expect that the bolt carrier would have been given weight reduction cuts to increase reliability of cycling, as the 7.62×39 carries ≈20% less energy than the 7.62×45, but the author is yet to confirm this. Production of conversions likely stopped around the time production of 7.62×39 VZ58 began. Some VZ52/57s were given as aid to Czechoslovakia’s Warsaw Pact allies such as Vietnam and Cuba.
The example of a VZ52/57 lives in Danmark in the hands of a private sportsman. The self loading capability has been deactivated to comply with the laws of the country, but it will still fire as a semi-bolt-action. Some VZ52/57s have been imported to the United States and Canada but the standard VZ52 is more common on these markets.