Nikon Prostaff 5 set up using Spot On a smart phone app to estimate the bullet drop at different ranges. The scope is a 4.5 X 18 X 40 mm with BDC bullet drop compensation and parallax adjustment or some say side focus. Parallax adjustment is more then just focus it takes care of some of the eye reticle alignment problems at longer ranges, but if you want to learn more look it up. The AR15 is mostly Anderson it has a 24 inch barrel chamber in 5.56 Wylde first rounds were Federal 223 55 gr just to get close the groups were Federal 223 50 gr varmint tip which is almost a frangible round it completely explodes after about 4-5 inches of penetration and comes out at about 3600 fps. I bore sighted it and shot 25 yard to make sure it was close then backed out to 100 yards shot about 3 groups of 3 to the center using a Caldwell Matrix Shooting Rest in the prone position. Then went to the smaller corner targets and had some fun with steel targets.