Try this forsighting in. I learned this from shooting a Bow. Draw a straight line on a piece of cardboard (horizional) and sight in on that line, dont worry about where they go on the line, you just want to be on the line for now. I usually do this at 30 yds to start off. Once your happy with them all on the line, move the target to 50 yds and do the same, once on the line I move the sight up and then shoot so Im about 2" high above the line at 50yds. Now draw a line up and down on the target to sight in for left and right, move the scope accordingly untill all the shots are on the line again. Now shoot at 50yds and all your shots should be 2"high at 50yds and tightly grouped. This will put you dead on or a ltttle higher at 100yds. Trying to sight in for left and right all at once is tough, this may seem harder to do, but after you try it you'll never go back to the old way of trying to do the left, right ,up and down all at once.And you'll be surprised at how much more tight your groups are. This way your only concentrating on one aspect at a time of sighting in. I challange anyone to at least try this method and see for yourself at how much tighter your groups will be. This has helped many guys from our Bowhunting Club shoot quarter sized groups at 50yds with a Bow, and broadheads at that. And we now sight it our guns this way too.