Are You At Zero?

So, you just bought a new rifle, scope, bases, rings and a couple of random boxes of ammo they had on the shelf at your favorite gun shop. Congratulations. Keep living the dream. I hope it is the exact rifle you’ve always wanted. To save yourself some time, money and shoulder bruises, you asked an employee of the gun shop to mount the scope for you. Hopefully he checked for proper eye relief, and ensured that the scope’s vertical post is in alignment with the bore. Heck, you might have even parted with the extra $5-$20 to have your new scope bore sighted as well.

Okay, so now comes the fun part…sighting in your new rifle. Yes, that’s right. A bore sighted rifle is not ready for the deer blind, varmint shooting rest or even the carbine class for which you signed up. No, it’s time to go make sure that your scope is truly sighted in at a meaningful distance for the kind of shooting you intend to do.

I’ve heard and read every sight-in method out there. Most are a complete waste of ammo and time (not to mention your shoulder if you’re shooting a magnum cartridge). The first method that was taught to me during my youth was quite random, and called for “keep shooting and moving the adjustments until you hit where you aim”. Okay, that sounds great but it never really works out quite like you expect. I’ve even been told to start with your target at 100 yds, look down the bore (if it’s a bolt action rifle, or eyeball it down the side of the barrel if it’s not), and start whacking away. Both of these methods will cost you way too much in the way of ammo, and will eventually force you to endure shot after shot of recoil. Eventually, even the strongest mind will begin to flinch. At that point, you’re done. And, you’re rifle still isn’t sighted in!
Explaining recently to a friend who is just getting into the shooting “habit” how sighting in really worked, I decided that I had to get this on paper to share with everyone else. Because, it isn’t a mysterious process, and it’s actually fairly simple.

First, place your target 25 yards away from your shooting bench. Make sure to use one of those targets with gridlines 1 inch apart, as it will be easier to determine what kind of adjustments need to made based on your point of impact. I prefer the ones that have an additional bullseye in each corner. Next (I simply cannot stress how important this step is) place your rifle on a solid rest. A solid rest can take any number of forms. You may choose any of the range/varmint style rests that hold the entire weight of the rifle. There are even some into which you can strap the rifle so that it won’t move at all, even when fired. Or, you can do it the old fashioned way with 5 or 6 sandbags. Whichever rest you choose doesn’t really matter. Just make sure that it’s comfortable. With the rifle in the rest and in a shooting position, adjust the power on your scope (if it’s a variable power model) to the highest setting where the target is still clear. This will usually not be the scope’s highest setting, but it will probably be relatively close (yes, I’m overlooking the fact that some scopes have a knob for parallax adjustments at this time. Now, look through the scope at your target, and close your eyes for 10 seconds. When you open your eyes, you should see the exact same sight picture that you saw before you closed your eyes. If you don’t, re-adjust your seating position and the rifle’s position until you do. Now it’s time to load your first round. Proper shooting technique here is a must. Squeeze the trigger while making sure that you don’t flinch from expectation of recoil. Keep your crosshairs on the center of the bullseye, take a breath, let it part way out and let it fly.

If you felt good about that shot, it’s time to make some adjustments. If not, figure out what you did wrong, correct it and try it again. Note that most scope adjustments (clicks) represent a distance at 100 yards. Most commonly, this is ¼ inch at 100 yds. But, we’re at 25 yards. Therefore, since we’ve cut the distance down to ¼, we need to make the same adjustment to the number of clicks that we process through the elevation and windage turrets on our scope. To do this, we need to multiply the number of clicks we would make at 100 yards by 4. Let’s say that the point of impact from your first shot was 3 inches to the left, and 2 inches low. You’ll need to move your point of impact 3 inches to the right, which would be 12 clicks at 100 yards. At our initial distance of 25 yards, this means 48 clicks (12 x 4 = 48) to the right on the windage knob. Likewise, you’ll have to adjust the elevation knob 32 clicks up. Note that it is always better when making large adjustments to overdial by a couple of clicks before moving back. This allows the inner workings of the scope (springs, etc…) to settle in more accurately. Therefore, dial in 50 clicks of right windage, and then back off 2 clicks in order to settle at 48.

This process at 25 yards should put you within the ballpark at 100 yards. Note that setting the elevation to overcome the probable 1.5 inches from the rifle bore to the place where the crosshairs meet in your scope may cause you to shoot an inch or so high at 100 yards. Especially if you’re shooting a cartridge with a high muzzle velocity.

Now it’s time for the “fine-tuning”. This is where those ¼ inch clicks at 100 yards really come in handy. Place your target at 100 yards and repeat the same breathing/trigger squeeze with a 3 shot group. If you did your job right, and all of the shots felt good, average them to determine the average point of impact. If you know that you blew a shot, disregard it, mark the spot and re-shoot it. Once you have a solid average, make your final adjustments. If you shoot multiple 3 shot groups, make sure to give your barrel time to cool. Cool barrels shoot more consistently, and under most shooting situations, you want your first shot to count. First shots will always come from a cold barrel. At the same time, allowing time for the barrel to cool will also give your shoulder a rest.

You’ve heard plenty of folks say that they’re sighted in 2 or 2.5 inches high at 100 yards, thus making the rifle’s zero at 200 yards. Although this method is impractical for benchrest shooting, it works out nicely for hunting. Most of your standard “deer” cartridges from .243 Win, right up to the .300 Win Mag sighted in using this method will allow you to hold right on the heart/lung area up to approximately 300 yards and still make a solidly ethical kill shot on a game animal. Taking the worry of bullet drop and hold-over (ie: Kentucky windage) out of your hunting kill shot equation will give you a better opportunity of making a clean kill. However, if you intend to use any of the new ballistic compensating, or mil-dot reticles, you will need to compare the ballistics of your rifle’s preferred load to the scope’s owner’s manual to determine what is the best zero distance for your situation.

Just a few things to remember, your rifle may “like” one type of ammo better than others. Bullet weight, in conjunction with the barrel’s rate of twist will allow certain loads to shoot more consistently and accurately than others. My advice is to fine-tune with a few different loads (specifically bullet weights), and stick with whatever load seems to group the best. Note also that barrel cleaning is important as well. Although few rifles call for a barrel break-in period, you should still run a patch cloth through it to eliminate carbon buildup every 7 to 10 shots during the sight-in process (yes, some manuals call for cleaning every 3 shots, but I’ve just never found that to be productive). Occasionally you will run across a rifle like my early 2000’s manufactured Winchester Model 70 in .270Win. These rifles don’t have the greatest accuracy reputation, but I’ve found that mine will shoot sub-1 inch groups at 100 yards. But, this will only happen with 140 grain projectiles that have a muzzle velocity of at least 2,900fps. This is a relatively specific load, but there are enough options out there these days to keep it shooting well.

However, this rifle has a very specific issue, that was extremely frustrating until I figured it out: the first bullet fired after a thorough cleaning and complete bore scrubbing will not shoot accurately. I’ve solved this problem for hunting purposes by only giving it a once-over bore cleaning after my pre-season range trip to confirm zero. If possible, I’ll even burn a round through it before the season starts so that my first shot on game is actually my second shot since cleaning. The moral of the story is that you will get to know your individual rifle, it’s likes and dislikes. You will also learn how to get the most out of it. Hey, who would have guessed that I could get 1 inch groups from a $350 Winchester Model 70 that I bought from Wal-Mart back when they still sold guns!