Posted in Featured | 1 Comment

Zeroing Rifles

Zeroing Rifles
Do It First If You Expect
To Hit Where You Aim.

No matter what sort of sights a rifle wears—peep, open or optical—the thing must be zeroed. Yet it seems the knowledge needed to properly zero a rifle escapes many people. Most autumns I help some younger shooters get their rifles ready for hunting season. Many times I’ve had their parents say, “They only need to practice a little bit. The scope was bore sighted when we bought it.” A variation of the theme is, “They only need to practice a little bit because the rifle was sighted in last year.”

A very revealing exercise to both parents and young folk after they assure me the rifle was bore sighted properly at the store is to put up a target at 100 yards. Then I tell the kids, “From the sandbags, take one shot holding the crosshairs dead center.” When that shot is errant, by inches or feet in some random direction, then kids and parents finally understand that bore sighted is not the same as zeroed!

And the same thing happens after I’m assured the rifle is still sighted in after last year’s hunting. They seldom are, even though they sat untouched in closet or gun safe for most of a year.

Zeroing a scoped rifle has become a matter of simplicity. Almost every scope sold today has arrows on the elevation and windage knobs showing which way to move bullet impact. Most also tell how many MOA each adjustment increment relates to. (MOA = minute of angle, or 1.047-inch change at 100 yards. For practical purposes, it is an inch change at 100 yards.)

Iron sights—peep or open—are a different matter. Some experience with such things goes a long way to getting a rifle properly zeroed. And let me stress this. A rifle not zeroed is next to worthless, and almost as bad is a rifle whose zero has not been verified by paper-target shooting. That last statement may fall on some hostile ears for I’ve been told by many Montana old-timers that sighting in on rocks is perfectly adequate even though the rock is of an undetermined size at an undetermined distance.
(Personally, I enjoy shooting at rocks myself. It’s fun for someone to pick one out and then challenge you to hit it. This is called plinking and it’s recreation. It has nothing to do with zeroing a rifle.)

Let’s look at some scope zeroing details first. Bolt actions are the easiest because you can remove the bolt, set the rifle on sandbags and look through the barrel so a bull’s-eye (at 25, 50 or 100 yards) is centered in the bore. Then holding the rifle steady turn scope knobs until the crosshairs are also on the black bull’s-eye. You still are not sighted in, but you are bore sighted just as effectively as done in a gun store with their little gadgets.

With rifles having bolts not so easily removable (lever guns, semi-autos, etc.) then it’s more a trial and error matter and about the only time I feel having a rifle/scope combo bore sighted at a store is beneficial. Here you want to start your shooting close—say at 25 yards with a big paper target. In times of desperation I’ve had to pick out a spot in the snow or (I’m back to it!) a rock on a hillside. Then, with someone watching for point of impact, I’d fire at it.

zeroing2

Scoped rifles or iron-sighted rifles must be zeroed in different ways (above) but
they still must be zeroed to be effective. Hunting rifles are generally set for a
given distance and then the shooter “holds off” for elevation at different ranges.
Tactical rifles are zeroed but then their scopes can be adjusted for bullet drop
at different ranges (below).

zeroing3

Tips

Scope Tip No. 1: If possible, use mounts with mechanical windage in the base such as standard for Leupold mounts. Then do all the rough windage zeroing with the mounts and save the fine-tuning for the scope itself. Remember to move the rear of the scope toward where you want the bullet to impact. Scope Tip No. 2: Get the scope properly straight in the rings. If you are mounting it yourself you can even align it with some 90-degree angle in your home or shop’s construction. I’ve used window frames. Scope Tip No. 3: When you have point of impact fairly close to zero, shoot 3-shot groups and adjust from the group’s center. This is far more reliable than adjusting from a single shot.

Sighting in with iron sights is a much more complicated matter. Let’s consider barrel-mounted hunting sights first, such as found on vintage Winchester and Marlin lever guns, modern made replicas thereof and a vast array of other types of iron-sighted long guns. Almost all of these, when in rifle form, have sights set in barrel dovetails—front and rear. Not so for carbines. Their front sights are either part of the front barrel band or blades set in studs silver-soldered atop the barrel.

Moving a dovetailed rear sight is easy. First ascertain whether there is a “cramp” screw in it. This is a screw to ensure tightness even if some wear or age allows the rear sight to loosen in its dovetail. This screw—if there—need be removed. Then with brass punch and hammer and with the rifle on a solid surface, tap on the rear sight to move it in the direction needed. Just as with scopes, a rear sight should move in the direction you want the bullets to move.

Now, here’s Iron Sight Tip No. 1: Before pounding on the rear sight pad the rifle so it’s wood, plastic or metal does not become marred. Also, having someone holding it tightly helps. If a sight is recalcitrant about moving, then dose it with some penetrating oil for awhile. This is often needed with vintage rifles.

The same is true for front sights only in reverse—if the sight is set in a dovetail. That is, drift the front sight in the opposite direction you want the bullets to go. A natural question here is, “How much do you move the sight?” Well, that is purely a shoot-and-see proposition. Move the sight perceptibly and shoot—again, a 3-shot group is better than a single round. Here’s Iron Sight Tip No. 2: In order to perceive how much either a front or rear sight has moved, put a strip of masking tape along it. Then with a pencil, mark some index lines on sight and tape. The amount of movement will then be easy to discern.

So far we have discussed only zeroing iron sights for windage. What about elevation? Some open-sighted rifles have a rear sight with slider so elevation can be raised. What if the rifle still shoots too high with the rear sight bottomed out? Or what if the rear sight’s slider does not give enough elevation to bring point of impact where needed?
This is when the front sight must be replaced or altered. Again, keep in mind the front sight must be moved opposite from where you want bullets to impact. If a rifle is impacting bullets too high, then a taller front sight is needed; too low and a shorter one is required. Things can get sticky here if some impetuous soul starts grinding or filing on the sight without having some backup sight blades on hand. I know!

zeroing4

Note the differences in these replica and original Winchester Model 1873’s.
The front sight on the top carbine (Cimarron/Uberti) is integral with the
front barrel band. On the second down Cimarron/Uberti Sporting rifle and
the third down original Winchester the front sights are dovetailed to
the barrel. On the original Winchester musket at bottom the front
sight is set in a stud silver-soldered to the barrel.

zeroing13

A specific load must be settled upon before zeroing. These two groups were fired
with vastly different loads in the same rifle using the same aiming point.

zeroing14

Battle zero for most European military rifles is about a foot high at
100 yards, which translates to zero at about 300 meters.

It is amazing how many sight blades are out there and how inexpensive they are. For instance, I just ordered six of varying heights for Mauser military rifles from an Internet auction site. Cost was less than $20. It is a little-known fact that some makes of military sight blades were manufactured in a wide height variety so individual rifles could be zeroed. For American Model 1917’s and British Pattern 19’s there were 11 different heights made. (They are interchangeable between the ’17’s and ’14’s.) US Model 1903 and ’03A3 Springfields had 5 heights of sight blades. (Those were not dovetailed—the blades were pinned into studs.)

Here is Iron Sight Tip No. 3: If you have many rifles of the same make needing front sight adjustment, it helps to have one of the special tools (a “sight pusher”) made especially for that. I have enough Mauser military rifles to justify the tool’s cost. It sits over the end of the barrel and by screw pressure will push the sight whichever way is necessary. Instead of pounding on sight blades I can now minutely move them and do so quickly. My Mauser tool came from Accumounts.

When drifting rear and front sights in their dovetails, especially in vintage firearms, don’t be surprised if one or the other ends up sitting noticeably off-center. Admittedly, this looks funny. Here is Iron Sight Tip No. 4: To lessen the visual impact of an off-center sight, take up part of the adjustment needed with one sight and part with the other—taking for granted here both front and rear sights are in dovetails. For example, if a rifle is shooting quite a bit left of center, then move the rear sight right and next move the front sight left. This way when zero is achieved, neither one should be too far off center.

Now we get to tang-mounted peep sights. It would actually take a book to fully describe all the ins and outs of old-style, target-grade Vernier tang peep sights and their corresponding front types. Space will not allow all that here but we can hit the high points. One important detail is tang-mounted sights need to be set level and the fact is not all rifle tangs are square with the rest of the action. Therefore, it is not uncommon for tang sights to need shimming to make them straight.

First we need to know which way they lean. A very detailed way is to hang a plumb line from your shop’s ceiling so it is directly in front of your rifle’s bore when it is secured in a vise. Then raise the sight’s eyecup and see if it stays aligned with the string as it climbs the sight staff. If it moves off right or left then you know which way the sight leans. A far easier but less precise method is to use a small T-square with spirit level, holding it against the side of the sight staff. Then shim the base, until the spirit level says the sight is square with the world. Here’s Iron Sight Tip No. 5: You don’t have to keep a bunch of different thicknesses of brass shims on hand. Pieces of soda or beer cans work as well.

And we’ll end with the idea of mechanical zero. For a windage adjustable peep sight to be worth a hoot, the rifle must have a mechanical zero. The rear sight must be at its center setting when the rifle is hitting zero. This way, as wind conditions change, adjustments can be made. But if the breezes die, setting the sight back to zero returns the point of impact also to zero. Otherwise windage adjustable rear sights are useless in regards to repeatability.

I would like to say all 70 or so of my current rifles are zeroed as this is written. It takes time and plenty of ammunition. I have the latter but must ration the former. So let’s say my zeroing chores are a work in progress.
By Mike “Duke” Venturino

Accumounts
P.O. Box 1802
Troy, MI 48099
http://gunsmagazine.com/company/accumount/

>> Click Here << To See More Photos

Read More Features

G0714_300

Order Your Copy Of The GUNS Magazine July 2014 Issue Today!

Download A PDF Of The GUNS Magazine July 2014 Issue Now!

Share |
  1. Hey “Duke”

Leave a Reply

(Spamcheck Enabled)