Wby460, You don' t say if the point of impact (PI) moved with your vert. adjustment or not. If not, the scope is bad. If it did, but not enough, your mounting is wrong or at least needs shimming. You can buy or make steel shims for use under your base(s) to correct your problem. Be sure to center the vert. adjust. before you shim so you have full range of adjust. when you have it roughly centered with shims. This is where a bore sighter comes in handy. Also, I always shoot at 25 yds. to rough sight a scope as that will put me in the black at 100. After that, shoot at 100 for load development and shooting practice, and longer distances for hunting practice. The best way to make 300 yd. shoots is to practice them. Good luck.