Firstly I'm assuming your speaking of a detachable box magazine... If so the problem won't be getting the round to fit a magazine but getting the magazine for the rifle. The problem will likely be the action screw spacing.. A magazine for a 300 WinchesterMagnum magazine will feed and function the 350 round.. The stock will require modification to get the hardware for the DBM to clear and function, but it wouldn't be difficult..