On that rifle a 1-4X20 of your choice. A 2-7X is a very distant 2nd place finisher. If I already had one laying around I'd use it, but if buying one anyway just go with a 1-4X scope.
Up close and fast 1X is faster than irons and a lot better than 2x than you'd believe until you try it. On 4X you have more magnification than you really need
