Next, you’ll need to construct a target large enough to catch every shot out to the distance you plan to shoot. A target frame that is 8 feet tall and 2 feet wide with a good base and frame will serve your purpose well. Attach some cardboard to cover the frame and staple a target to the top. Choose a target that you can see easily at long range. You can also take a wide felt-tipped pen and draw a large 18-inch cross at the top of the cardboard.
Begin at 100 yards, and shoot a three- to five-shot group, holding dead-on the center of the target. Then, move the target out to 200 yards. Shoot another three- to five-shot group carefully holding to the same point of aim. Continue this out as far as you choose. After each group is shot, take a felt pen and circle the shots. Especially at 100 and 200 yards, the shots may be close enough to look like a single group, and you’ll want to be able to differentiate between the groups.
The 300-yard group will be noticeably lower than the first two, and beyond 300 the distance from the point of aim will progressively grow. I draw a line down the center of the target to the bottom group and simply measure the distance from the center of the target to the center of each group. This shows exactly how far your bullet drops from the point of aim at each distance shot.
If your scope has one of the trajectory-compensating reticles using mil-dots, hash marks or circles, shooting this exercise will verify the exact subtension between the marks at various ranges. Often they will vary a bit from what is on the carton or in the instructions
Take note of your group sizes at each range. Understand that as the range increases, so does your chance to be off the mark because of the inherent accuracy of the rifle and limitations of shooting ability. Keep in mind that we all pull a shot occasionally. Look closely at my target, and you’ll see but two shots in the 300-yard group. The third was a called bad shot 5 inches high and 5 inches to the right of the group—a very good reason to use five- or even ten-shot groups if you are trying to be exact in your determination of real-world drop.
Shooters love to brag about and compare their 100-yard groups, and there is certainly some justification in that pride. Like many, I have a few of those spectacular one-holers tucked away in frames and scrapbooks around the Wyoming homestead. But if you want to have a reasonable chance of bullet meeting flesh out past a quarter mile, you’ll need a pretty good idea of how far to hold over with a particular rifle and load. Once you get into it, you’ll likely find it’s a lot of fun and very educational.
A few caveats: Do not shoot long distance groups on a windy day. All you will do is waste ammo and get frustrated. My latest 400-yard group fell a few inches to the left of the others. This was due to a mild breeze that arose while shooting that group. Always verify your distances with a range finder, and remember that hot or cold days and significant (say, 6,000 feet or more) elevation changes can affect your point of impact.