This slug gun is sighted-in to strike 2 inches high at 100 yards. Even slow-moving projectiles can be zeroed for maximum efficiency.

By Ralph M. Lermayer

I hate math - always have. I tried to duck out of my entire last year of high school algebra, got busted and spent a whole summer making it up so I could graduate. All I cared about were journalism and English courses, and spending every available moment outdoors, gun, bow or fishing rod in hand.
 
Two pivotal events in my life did pique my interest in numbers. At a young age, I discovered money and thought it would be a good idea to learn how to count. Later, I learned that applying just a little bit of numerology to how I set up my rifles could extend how far and accurately I could hit and kill game. Suddenly, numbers mattered.
 
Apparently, I'm not the only shooter with an ingrained aversion to numbers. With the elk, antelope and deer openers just weeks away as I write this, the local commercial range is abuzz with activity. Hunters sighting-in a new rifle or checking to see where "Ol' Betsy" is hitting fill the benches.
 
I spend considerable time at that range each year assisting those shooters and helping with range safety. Sadly, eight out of 10 of those pre-season sighter-inners, regardless of caliber choice, still choose to zero their rifle to hit point-on at 100 yards. Most of these shooters are open-country hunters whose shots are likely to be over 100 yards by a large margin. That's the wrong call, and in many cases, the built-in reason for many missed or wounded animals every year.

Does it Matter?
If you hunt dense cover and shots rarely exceed 75 yards, simply sight-in at that range, and forget the rest of this. If, however, your stand overlooks an agricultural field, power cutline, logging road or includes any kind of open country, take heed.
 
If the numbers at my local range are any indicator of the national mindset, then eight out of 10 reading this are building in a miss. If you're among the minority who already know it, please pardon my oversimplification.

Screenshot of RCBS.LOAD reloading software.

The Factors
Gravity works the same no matter how fast an object is moving. Assume your rifle barrel is perfectly level - caliber and bullet weight don't matter - fire a shot. At the exact moment that bullet leaves the muzzle, drop a bullet of the same weight and size held in your fingertips from exactly the muzzle height. Both the fired bullet and one you dropped will hit the ground at the same time. Cool concept, huh?
 
Gravity begins pulling your bullet down the minute it leaves the muzzle. If you want it to go farther before it drops, you need to start out by pointing it upward, a bit higher. How high? That depends on a few easy-to-find details. Let's look at the chart and apply just a little of the hateful math.

The numbers will vary slightly depending on your caliber, bullet weight and starting bullet speed (muzzle velocity). I will illustrate the basic concept with the ever-common .30-06 firing a factory-loaded 180-grain bullet at about 2,800 fps, or the average muzzle velocity for such a round. While many of you do shoot such a load, many of you don't.
 
Precise numbers for your particular load can be found in several places:
1) The ammo manufacturer's website; 2) The ammo box; 3) The ammo catalog your retailer keeps behind the counter; 4) Any current loading manual you can beg or borrow from a friend, or sneak a peek at on dealer's shelves; or 5) the absolute best, one of the great ballistic programs offered on CD by RCBS, Sierra or a host of other suppliers. If you know what you're shooting, you'll find the best way to max out your rifle in one of these sources.

The Numbers
Back to the .30-06. The numbers quoted here come from the current "Hornady Handbook of Cartridge Reloading," the Winchester Ammo Catalog, and a vintage but still usable RCBS Load program I downloaded on my PC about six years ago. For the nitpickers who spent time polishing their slide rules while the rest of us were out hunting and smelling like gun oil, these numbers will differ slightly from manual to manual, even though the bullets are similar. The slight differences are inconsequential; they don't matter. They are the result of different barrel dimensions, lengths, velocities or bullet styles they chose to use for their testing.

Hunters can print the trajectory of their favorite load and tape it to their rifle's buttstock for quick reference in the field.

There are, however, huge differences when bullet styles change significantly. While most spire points with the same general style and weight are very close, changing to a round-nose bullet or a semi-flat point as found in ammo designed for lever guns will alter the proper sight-in number quite a bit.

More streamlined bullet shapes offer less resistance to the air and hold their speed better. That means they go farther before gravity messes with them too much. That shape has a rating, a form factor or an efficiency-in-flight number. It's called the "ballistic coefficient" or BC. Be sure to find the tables for the precise bullet you hunt with or at least one with the same BC. Once you choose it, the same sight-in philosophy will greatly extend the point-and-shoot range for any bullet.

Bullet Choice
Winchester has been loading a dandy little .30-caliber bullet for years. It's both economical and accurate. The 180-grain Power Point Plus has a well-deserved reputation for performing on game. Similar designs are Remington's Core-Lokt, Nosler's Partition, Federal's Fusion and Hornady's 180-grain SP#3070. All have a relatively high BC. Factory loaded in a .30-06, bullets exiting a 22-inch barrel will be traveling around 2,800 fps.

Your Way
Let's sight that bullet in to hit dead-on at 100 yards. Look at the chart. You're okay from the muzzle out to about 150 yards, but at the 200-yard mark, you're hitting almost 4 inches low. At 250, no big stretch for an '06 along a power-line cut; you're down about 6 1/2 inches. What does that mean? Your buck breaks cover on the edge of the timber, down that cutline or across that beanfield. You hold for the classic shot behind the foreleg, slightly below body centerline, the biggest area for a heart/lung hit.

The bullet falls 6 inches low, resulting in a low brisket graze. The animal reacts to such a hit by dropping low or actually folding over. You high-five your buddy and scramble the 200-plus yards to find no buck, but a good blood trail. Brisket hits bleed well - for a while. The next several hours are spent trailing, the blood gives out (brisket wounds eventually seal), it's dark, and you head back to the truck disgusted. No buck!

Another Way
Let's try that another way. You sight-in to hit about 2 inches high at 100 yards. You're now dead-on at 200 and only 3 inches low at 250. That pretty much means you can forget the distance factor from point-blank clear out to at least 225 yards, hold where you need to and load up your buck in the pickup. You won't swing more than 2 inches from dead-on throughout the whole distance. Two inches high at 100 and 2 inches low at 225 keeps you nicely in the kill zone. Sighting to hit 2 inches high at 100 yards is a far better way in any rifle that will see medium- to long-range action.

Better Yet: Maximum Point-Blank Range
The above will get most people by, but there's yet an infinitely better way. You'll need the use of a computer. Suppose you decide that as long as you can stick a bullet inside a 6-inch circle in any animal's vitals, you'll kill it. If we could sight-in in such a way that our bullet would never be more than 3 inches high or 3 inches low, how far away would that allow us to simply "point and shoot?" There is a way. It can be calculated for any bullet out of any firearm, and you don't have to do any math!
 
Using the RCBS computer program, we tell it we are using a 180-grain Hornady load (it knows the BC) with a muzzle velocity of 2,800 fps. We establish a 6-inch-maximum diameter, 3 up, 3 down. Elk and moose hunters could change that to 8 inches. Then we simply click "Optimize Maximum Point-Blank Range."

A chart and graph pop up and tell us if we set our rifle to hit 2.7 inches high at 100 yards, then we will be within the 6-inch kill zone clear out to 275 yards. Never any more than 3 inches high, and only dropping to 3 inches low at 275 yards. Your maximum "point-blank, point-and-shoot and forget-the-distance range" with that setup is clear out to 275 yards.

Ain't numbers grand, especially when you have a computer program to do all the calculations for you?

The Rest of the Equation
In reality, 275 yards is the outer limit of most shooters' ability, but it's nice to know that the humble .30-06 rifle with a factory load will stretch that far. Of course, we're making several assumptions here. One, that the accuracy of the rifle and skills of the shooter are up to the task of hitting the target; and two, that the bullet will have enough energy left at that distance to punch through hide, muscle and bone and get the job done.
 
Back to the manuals and a few more numbers. Energy kills game. Energy is the result of velocity times weight. Yes, that's a bit of an oversimplification, but you get the drift. To figure it, since we know the bullet weight, we need to know how fast it's still going when it reaches that max point-blank range. The simple charts tell us, at 300 yards, the bullet has slowed to 2,189 fps and is delivering 1,914 foot-pounds of energy.
 
Is that enough? I've always relied on a number published by P.O. Ackley clear back in the '50s. With muzzleloaders, handguns or rifles, it's never let me down. Ackley suggests a minimum of 900 foot-pounds of energy is required for deer and 1,500 for elk. Thus, the Hornady bullet (or any of its counterparts) used in this comparison has plenty of oomph for either.
 
Things get snappy when you move up to the likes of a 7mm Rem Mag zipping out a 140-grain bullet at 3,000 fps, and drop substantially when you go down to the likes of a .30-30 shooting a flat-nose bullet at about 2,400 fps. However, in both cases, there is an optimum sight-in, and it's rarely dead-on at 100 yards.
 
Just because the average shooting distance at most commercial ranges is 100 yards from the bench, and a bull's-eye with a bunch of holes square in the middle gives you a nice fuzzy feeling, don't do it. For most modern flat-shooting centerfires, 2 inches high is a good rule of thumb. For the likes of a .30-30 that may be asked to poke one out to 150, an inch-and-a-half is a better call, but for the ultimate in the ideal sight-in height, find a ballistic program and play the numbers. You don't even have to do any math, just click and print!   

Ralph M. Lermayer
GunHunter Magazine - December 2006
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