My gues is measure the outside barrel diameter and give JES a call they will tell if if there is enough "meat" in the barrel my greater suspicion is int he magazine, i am not a expert on which rotary magazine size you might have all my conversions were based on a 308 rifle, i am sure there is someone here that can commnet on the magazine, I know even in the 308 guns the magazine is tight when you neck up to the 358.
