Recusant
Hellcat
Here's a rifle that was imported by Century Arms back in the day. These started out as the VZ 52 that was chambered for the 7.62 X 45, but with pressure from the Soviet Union they were rechambered for the 7.62 X 39 and re-designated as the VZ 52/57. These rifles were given new barrels with chrome lined bores as well as a different magazine. I'm not sure if this was done by the Czechs or after they arrived here, but some were converted by fitting an insert into the chamber, because 7.62 X 45 ammo was expensive as well as almost impossible to find. This rifle was done in 1958 and notice from the picture that the Czech conversations have a pin that was installed that locks the new barrel to the receiver. Other conversations don't have this pin.
http://milsurpcollector.com/31.html
http://milsurpcollector.com/31.html