OUTDOORS: SIGHTING IN: THE FOUNDATION FOR GOOD SHOTS WHILE IN THE FIELD

It certainly behooves a hunter for the bullet from his rifle and the sights through which he looks to have something in common -- like the same target.

Nobody can hunt effectively if his rifle doesn't shoot to the point seen in his sights. Aside from pure outhouse luck, if the gun doesn't shoot where you look, you have little chance of connecting on game.

With the onset of firearms deer hunting, numerous whitetail seekers will set off into the woods and fields facing an impossible task. They'll go hunting with rifles that aren't sighted in, or are sighted in improperly. They may work hard to get opportunities to tag deer, but when those magical moments arise, they'll launch bullets into who-knows-where.

Rifles and the telescopic sights they most frequently wear don't know each other until they are adequately introduced on the firing range. When a scope is first mounted on a rifle, it doesn't mean that where the bore of the rifle points and where the scope looks is the same spot. Almost always, it's two different places.

A gun shop may collimate or bore-sight a rifle/scope combination, a step that brings two planes -- bullet path and line of sight -- into close proximity. However, that step is but a generalization. It's not finely adjusted enough for hunting purposes. A collimated or boresighted rifle may be off a foot or more at a realistic hunting range, well far enough to ruin a chance at a deer.

Sighting in for most rifle/scope combinations, after collimation or bore-sighting, begins at 25 yards. That's almost a magical distance, for once sighted in dead-on at 25 yards, most rifles will be roughly adjusted for reasonable long-range shooting, too.

The process should begin at 25 yards, bringing point of impact and line-of-sight together. The next step., however, is critical. Once on at 25, the shooter should check and adjust his sights at 100 yards.

Typical and effective sighting procedure is to shoot off a steady rest, a rock-solid benchrest being the best choice. Shots should be taken with unwavering, careful aim to eliminate as much human error as possible. After all, this is to test and adjust the rifle, not the shooter.

It works best with at least three-shot groups, taking the average point of impact of each group as the reference point.

Understanding how a scope adjusts is key to sighting in. Most scopes have either 1/4 or 1/2 minute of angle adjustments in the elevation (up and down) and windage (left and right) settings. A minute of angle is one inch at 100 yards. Therefore, for a scope with 1/4 MOA adjustment, one notch or click on the adjustment dial moves the point of bullet impact 1/4 inch at 100 yards or only 1/16 inch at 25 yards (because 25 yards is a fourth of 100 yards).

Correspondingly, a scope with 1/2 MOA adjustment comes with dial clicks that move the bullet impact 1/2 inch per click at 100 yards, or just 1/8 inch at 25 yards.

It's not rocket science, so don't panic. It is ballistic science, but you can handle it.

Let's say you're shooting a rifle scoped with a tube bearing 1/4 MOA adjustments. You fire a group at 25 yards, the bullets clustering two inches high and one inch to the right. Using the formula of 4 clicks per inch at 100 yards, or (multiplied by four) 16 clicks per inch at 23 yards, adjust the point of impact dials on the scope down 32 clicks (two inches worth) and left 16 clicks (one inch).

That should bring the bullets pretty close to dead center at 25 yards. Fire another group and see what you've got. If it's still off, finely adjust accordingly using the same formula until the shots are on the money.

An important point is to let the rifle barrel cool between firings of shot groups. Impact point may change with a heated barrel, and you'll be doing your hunting with a cool tube.

Once the 25-yard sighting is right on or very close, you can move to a 100-yards target. Do the same thing there, except apply the 100-yard factors. That is, to move bullet impact one inch, move it with four clicks with 1/4 MOA adjustment or two clicks on a scope with 1/2 MOA calibration.

In most cases, rifles should be adjusted to hit slightly high at 100 yards. Depending upon the cartridge and bullet combination, most probably should be set two inches high at that range.

Your chosen cartridge/bullet combination can be studied in the ballistic tables of an ammunition catalog. Trajectory charts there should tell you how your specific rifle can be best sighted.

The reality is that a bullet actually begins dropping from the line of launch the moment it clears the barrel. Sighted in with a scope, the bullet actually is fired slightly upward. Unlike the old, silly belief that bullets actually rise in flight, it's just that the barrel is angled upward a tiny bit in relation to line of sight.

The upward-bound bullet will intersect the line of sight at 25 yards (because that's where we're adjusting it), peak out just a little above line of sight, then sink below it again as it slows and drops out at long range.

For example, a .30/06 firing a 150-grain bullet can be zeroed at 25 yards, will reach a maximum of 2 inches, then will sink back to dead-on again at a little beyond 200 yards. At 300 yards, the bullet will be about 6 1/2 inches below line of sight. For effective hunting purposes for deer-sized game, you can figure an accurate, dead-on hold out to about 270 yards.

If, however, you sighted the same .30/06 dead on at 100 yards, at 200 yards the bullet would be more than 3 1/2 inches low, and out at 300, it would be down more that 13 1/2 inches from line of sight. In effect, the 100-yard zeroing would take 60 or 70 yards off the rifle's accurate shooting potential.

It's even more dramatic with a slower bullet.

A scoped .30/30 rifle firing a 170-grain bullet may serve best if it's zeroed at 1/4 inch high at 25 yards, which works out to 2 3/4 inches high at 100 yards. That's not too much variation to hit deer-sized vitals. By the time the relatively plodding slug reaches 200 yard, it's dropped to 2 1/2 inches below line of sight. That's about the maximum distance, because the bullet drops to a full 10 inches under line of sight at 250 yards.

If one sights the same .30/30 as zeroed at 100 yards, however, the bottom falls out more quickly. At even 200 yards, ti would be more than 8 inches low -- too far for a dead-on hold for a deer-sized critter.

While most deer are shot at distances of 100 yards or less, having a rifle properly sighted for long-range potential provides dead-on hold for both near and far, from point blank to that maximum distance. Sighting in for a closer distance makes the shorter shots fine, but it sacrifices some of the across-the-pasture capability.

However one sights in, the firing range experience will tell him or her what to expect when the trigger is pulled. To the contrary, there are those who, when they shoot and miss come hunting time, won't have a clue that their aim actually was good. They won't know it was the disagreement between the sights and rifle that sunk their season.

Steve Vantreese is outdoors editor of The Paducah Sun.