I have the Miniart M1942/1943 cannon and was hoping to make the M1942 version with an aftermarket barrel. Seems I cannot find anything though.
Hmm can’t find the kit you are on about from your description text, can you add the kit part number?
Scalemates list several options, but generic options for barrels so you might have to look up tanks that carried that gun
Also look up Polish Company RB Models
I managed to find this after looking up the 57mm gun. Hopefully this barrel will do the job.