EAA .45-70 Government Barrel Insert, Converts Shotgun to Centerfire Rifle Converts EAA/Baikal models IZH43, IZH43K, IZH43KH, or MP213 shotgun to a side by side rifle or rifle/shotgun combo. .45-70 Government caliber. The insert system holds the rifle barrel inside the shotgun barrel at the muzzle and breach. Fits only 12 gauge, 20", 2-3/4" shotgun with factory installed screw chokes and extractor.