5 Secrets to Sight-in a Rifle with Ten Rounds or Less

Sighting-in a rifle is a process surrounded by myth and misconception.  Many people believe it takes hours on the target range and ammunition by  the case full. Nothing is farther from the truth. Whether you have just  mounted a new scope, changed loads, or just need to verify zero before  the hunting season starts, sighting in is easy and takes ten rounds or  less. Here’s how.

Equipment Needed

You will need the following items to sight in your rifle.
  •  Stable shooting bench
  •  Sand bags or a rifle rest
  •  Standard head screw driver and or a U.S. dime, nickel, and quarter
  •  Sight-in target for scoped rifles centered on a 3’x3’ piece of white poster board
  •  Ballistic chronograph
  •  Note pad and pen
  •  Spotting scope
  •  Ballistic trajectory software
  •  Ammunition you intend to hunt with (ten rounds, minimum)

Bore Sighting

If you’ve just mounted a scope, you need to get it and the rifle barrel’s bore in rough alignment. If your rifle is a bolt-action, verify the weapon is unloaded and set it on either sandbag rests or a rifle stand such as a Lead Sled® so it is secure, in plumb, and pointed at a the sight-in target twenty-five yards down range. Remove the bolt and look through the bore from the breech end. Adjust the rifle’s position until the bore is centered on the target. Now, without touching the rifle, look through the scope. If the reticle (crosshairs) are not also centered where the bore is, adjust the reticle by turning the elevation and windage turrets with either the screw driver or an appropriate sized coin until it is aligned with the bore.

If your rifle is not a bolt action, you will have to use a bore-sighting device. These are simple to operate and available from both gun stores and on-line sporting goods retailers
If the rifle and scope are already bore sighted, you can skip this step.

Getting on Paper

After the rifle is bore sighted, pick a day with little or no wind and take the rifle to the target range. Tape your sight-in target on the three foot by three foot piece of white poster board’s center and mount it at the range’s 25 yard line. Such a large target, set close in, will ensure you see where the first shots hit.
Set up the chronograph per the manufacturer’s instructions and fire one round at the sight-in target’s bull’s eye. Write the velocity from the chronograph in your notebook, and observe where the shot hits with the spotting scope. Adjust the rifle scope for elevation and windage so the bullet should hit the bull’s eye. The turrets on most scopes move the point of impact (POI) one quarter inch at 100 yards for every click the turret dial is turned (check your scope’s owner’s manual for exact specs). At twenty-five yards this calculates to 1/32” per click (1/4” divided by 4). For example, if you need to move the POI one inch at 25 yards, turn the turret 16 clicks.

Let the barrel cool and fire a second round, the bullet should hit the bull’s eye or very close. If not, adjust the scope and fire again. Make sure the barrel is cool to the touch between shots. If the second shot is already on target, fire one more round and record the velocity. Calculate the average velocity from the three shot string. Do not clean the gun after you shoot. 

If you are not on, or close to, the bull’s eye after three rounds, have a qualified gun smith examine the rifle and scope.

Find Maximum Point Blank Range

There are several good ballistic calculators available free on the web, such as the one at shooterscalculator.com. Once you have the average velocity, plug that into the ballistic software. You will also need the ballistic coefficient (BC) for the bullet you are using. Contact the ammunition’s manufacturer for this data. Another alternative is a table with BC’s for many commercially loaded bullets at http://spoton.nikonsportoptics.com/spoton/spoton.html#:4 which you can access free on the web.

The ballistic software will tell you the Maximum Point Blank Range (MPBR) for your rifle and ammunition. If you are a premium LocaCarnivore member, see our post on MPBR for more detailed information about this important concept. The software will tell you where your bullet should strike the target relative to the bull’s eye at 100 yards for a given MPBR. Now, it’s back to the target range (preferably on the same day you collected the data).

Final Zeroing

Set up the target at 100 yards and fire three rounds. Again, make sure the barrel is cool between each shot. Retrieve the target and measure the three shot group’s average distance from the bull’s eye and the average distance center to center for the holes. 

Adjust the scope if needed to move the average POI to hit where the software dictates and then fire three more rounds. Measure the center to center distances for this group as well.  The three shot group’s center should average out to the desired 100 yard POI, if not, adjust the scope and fire three more rounds with cool-down.

Remember to measure the group sizes; you’ll use them later for more sophisticated work with the software if you plan to shot beyond the rifle’s MPBR, but that’s a topic for another LocaCarnivore post.

If your shots will not form consistent groups, or the point of impact does not move consistent with the scope’s adjustments, take the rifle to a gun smith.

That’s it. Your rifle is now zeroed to its MPBR for the current atmospheric conditions, and you used less than ten rounds start to finish!

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