Complex sentence: Another feature of this pistol is the use of polygonal rifling in the barrel (only on the vz.82 in 9X18mm caliber), which replaces traditional lands and grooves with a rounded polygonal pattern that has a more "hills and valleys" appearance.
Split into simpler sentences: Another feature of this pistol is the use of'polygonal' rifling in the barrel bore (only on the vz.82 in 9X18mm caliber). This unique feature replaces the traditional lands and grooves rifling design with a rounded polygonal pattern that has a more "hills and valleys" appearance.