SIGHT IN DISTANCE
I am ready to go sight in my new rifle, a 30-06, and want to know what's the best distance to do this.
From time to time, the discussion of "best distance to sight in a rifle" comes up. This is a subject that deserves to be looked at in depth, although there is seldom widespread agreement.
For years and years, for whatever original reason, the standard for accuracy has been expressed primarily as the size of a group or series of groups, measured in inches and fractions or decimals thereof, fired at 100 yards. It's kind of like the now widely accepted standard for acceleration time of from zero to 60 mph for cars, which was started by Tom McCahill of Mechanix Illustrated magazine. There are, of course, many exceptions to this. The 1000-yard shooters may prefer to check load development at, say, 300 yards or more. Around-the-course shooters may be most concerned about how their loads perform at 600 yards, and not give a hoot about 100-yard groups. Nonetheless, most publications report in terms of 100-yard accuracy, and most shooters head to a 100-yard range when they want to see how they're doing.
Unfortunately, the old 100-yard accuracy check is not as relevant as it used to be. I'd much prefer to see shooting facilities begin to update, at least a little at a time, by installing a few shooting points at 150 yards. There's a number of reasons to answer the "how come?" Among them is that most hunting scopes are calibrated to be parallax free at 150 yards, not at 100 yards. There are exceptions, but not all that many when it comes to scopes marketed in the U.S.
In a survey done about 15 years ago, that lasted almost two years and involved thousands of hunters, the average range that a big-game animal was shot was determined to be 164 yards; with 80 percent of the shots occurring between 130 and 200 yards. With that being said, perhaps the idea of 150-yard shooting points, and calibrating scopes at 150 yards, should instead be 150 meters. But this is the United States, and we're much more used to using yards instead of meters and quarts instead of liters.
Over the past several years, I've tried to take an objective look at the mathematics involved when comparing the viability of sighting in, or at least checking rifle and load accuracy, at 150 versus 100 yards. It's all good. We find out much more about a good bolt-action rifle's capability at 150 yards. Rifles that shoot sub-moa groups at 100 yards are about as likely to do so at 150 yards, but only if the load is working as well at that distance. The additional 50 yards has the ability to expose more in the way of bullet "faults." This is where you can find out just how concentric that bullet jacket is, or if the base of the bullet is square with the axis, or if the assembly of core and tip to jacket is right on. You won't necessarily be able to tell exactly what the problem is, but, on a windless day, if the groups are opening up disproportionately in that extra 50 yards, you can bet that something is wrong with the projectile itself. I'm talking hunting bullets here; target bullets have their own set of issues and can be squirrelly enough at various flight distances.
With most fairly flat-shooting rifles, I sight in one inch high at 150 yards. Then I check the point of impact at 100, 200, and 300 yards. In the case of pronghorn or coyote, a couple of instances where I will allow myself to take a shot at, say, 400 yards, I make darn sure that I have a good rangefinder and that I know how to hold, regardless of scope reticle, to make a solid hit at 350 and 400 yards. I field-verify such results, and never allow the advertising claims about any scope adjustments substitute for absolutely knowing what I'm doing. An old-fashioned person, I never make scope adjustments in the field; and I don't buy or use the scopes with "distance adjustment" features. Instead, I have learned that "holdover" notes taped to the forward portion of the left side of my scope (I'm right handed) are best for me.
Each person should make their own decisions about sighting in. I keep my 458 Winchester Magnum (the best big bear cartridge ever developed) set one inch high at 100 yards with 450-grain Swift A-Frame bullets. I can quickly pull it into my shoulder and smack grapefruit-sized rocks offhand at 300 yards. This gives me a great deal of comfort. I can't consciously tell you how much holdover I'm using. It has become second nature to be able to shoot it well. That's where you need to be. To get there requires more than a little practice. While you're involved in your own exploration of what works best, you'll be piling up experience. Meanwhile, talk to fellow shooters in your area about setting up a 150-yard range.
Incidentally, a minute of angle at 100 yards is 1.047 inches. At 150 yards, one minute of angle is 1.571 inches.
JDC