Now you can convert your IZH43, IZH43K, IZH43KH, or MP213 to a side by side rifle or rifle/shotgun combo. The insert system holds the rifle barrel inside the shotgun barrel at the muzzle and breach. Thus, creating a more accurate rifle than traditional side by side rifles. Calibers: (45-70, .308 WIN, .222, .223). NOTE: The barrel insert will only work on the above model shotguns that have the following features: 20-12ga/2.75 barrel, factory installed screw chokes and extractor.