I mainly collect and shoot ww2 era rifles and I have to say i love the k31. on a trip to Switzerland i picked up a set of diopter sights for shooting out to 350 yards and the iron sights do 1000yrds pretty well just the windage is a challenge since you have to guess since there is no adjustment. at 1000 yards it takes 2 or 3 shots to figure out point of aim on the iron sights.
i agree though that some basic research and even a visit to a match to ask questions should be done by the op.
1000yrd shooting is some of the most challenging shooting you can do because of the number of variables but when you do hit the target that is the most amazing thing.