I have collected hand guns for about thirty years. Last year I decided to get into long guns a little. I bought a S&W mp 15. I like the gun but at the moment I can't seem to hit the broad side of a barn with it at 100 yds. I do O.K. at about thirty yards. It has a Sight-Mark red dot sight on it that I had sighted in for me at a LGS. I thought about getting a scope with just a little magnification but I know nothing about scopes and do not even know where to start looking or what to look for. I believe the problem is either with the way it was sighted in or with my lack of shooting skills with a rifle, I don't think it is with the gun. any suggestions on what to get and how to sight it in would be appreciated. I shot the gun at 100 yds for the first time this weekend and only hit the target once in 90 rounds of trying. I do not want to spend three or four hunded bucks on a scope so please keep suggestions on a budget price. BTW the gun will be used mostly for targets and plinking.