An adjustable rest with a fore-end pad is your best route to a steady rifle when zeroing.

Incidentally, sight height affects zero because it determines the angle of the sightline to the bullet's arc. A flat line of sight that first crosses the bullet's path at 35 yards will cross it again sooner (closer) than a line of sight that's steep by virtue of high scope mounts. Keep that in mind when you're comparing points of impact with the data in ballistics tables, some of which specify a 1.5-inch gap between bore center and sightline at the muzzle.

To make things easy, I zero almost all my big-game rifles at 200 yards. That's a bit short for 7mm and .30 magnums, if a three-inch midrange gap is acceptable. But I'd just as soon have less lift. And a point-blank range of 250 yards is long enough for me. I rarely shoot at game farther than that; when I do, I can shade a little high.

A top-of-the-back hold with my .270 will kill deer to 350 yards--far enough to make me giddy. I zero my .30-30 Marlin and .356 Winchester at 150 yards, my .45-70, along with 12-gauge sabot shotgun slugs, at 100.

The Process
After deciding on a zero, you'll want to bore-sight your rifle. You don't have to be at the range, but you need to be someplace that affords you a long view toward a small, distant target. Place your rifle on sandbags or any rest that holds it still. Remove the bolt and line up the target in the center of the bore. Brace the rifle so it does not move. Adjust your scope so the reticle centers the target. It's that easy. The rifle is now bore-sighted and should plant bullets close to your point of aim at 35 yards.

Lever, slide and autoloading rifles and muzzleloaders require a collimator, an optical device you attach to the muzzle with a bore spud. The collimator shows you a grid that takes the place of a distant target. If you shoot with iron sights, zeroing is a live-fire proposition.

Try to pick a still day for zeroing. You don't want to fight the wind for control of the rifle, and you don't want to zero for a right or left drift. You can chronograph loads while zeroing and test them for accuracy. But it's best if you first zero with one load, then focus on other things. If you must change zero for a different load later, it won't take long.

My range isn't developed. It has a bench but no target boards. I substitute large cardboard boxes with white paper squares affixed. These white squares are my favorite targets. I size them according to the sight. For iron sights at 100 yards, they're a foot square or bigger. For a 4X scope, I'll use a six-inch square; for a 6X scope, I'll go with a four-inch square. If you're shooting a varmint rifle with a 16X or 20X scope, you'll want a much smaller block.

The white paper shows up plainly against a brown box, and holes are easy to see no matter where the bullets land. Black lines and target faces hide little bullet holes. I prefer square to round targets because they're easy to quarter with a crosswire. With a dot or a front bead, the corners of the square remain visible, clearly indicating if the sight is off-center. I also like these targets because they are as cheap as typing paper.

After you zero, get off the bench and shoot groups from hunting positions. The rifle may shoot to a different point of impact, and you need to note that.

Regardless of how your range is set up, your first shots should be at 35 yards--whether or not you've bore-sighted. No sense wasting even one bullet that might miss the target-board back or hit a target frame. If the bullet hits within a couple of inches of center, take the target to 100 yards and start zeroing in earnest. If it is off the mark at 35, adjust until you get a bullet at point of aim, then move. When preparing to zero for 200 yards, your goal at 100 yards is to print a three-shot group 2.5 inches above point of aim. Adjust the sight until that happens.

When you get beyond rough adjustments, fire at least two shots before making sight corrections. If those holes are more than an inch apart, fire another shot. Small groups tell you with greater certainty where to move the sight.

Proper Form
Group size is partly a function of rifle and load, but mainly it's a function of how still you hold the rifle and how well you execute the shot. Even with a benchrest, it's easy to make a bad shot. In fact, a bench can give you a false sense of stability--prompting fast, sloppy shooting.