National Match shooters click their adjustments. They do not “hold off” in attempts to get a centered shot. In other words, sight adjustments over “Kentucky-Windage”.
There are three types of zeroes:
• Mechanical Zero (MZ)
• No Wind Zero (NWZ)
• Known Zero
MECHANICAL ZERO (MZ):
Mechanical Zero (MZ): The rear sight centered equally left & right, exactly in the middle and bottomed out. Establishing a true mechanical windage zero is as simple as adjusting the sight all the way in one direction until it stops against the sides. Then carefully count clicks all the way to the other side. Divide that number in half and count that many clicks back towards the center. This is the mechanical zero. Once established, this zero is best marked with paint, as it will never change (click here for more on: marking your rifle).
NO-WIND ZERO (NWZ):
NO-WIND ZERO (NWZ): a sight setting that will deliver a centered shot when not influenced by wind conditions (think: the extremely rare opportunity of shooting in a tunnel, with no outside influence).
Solid NWZ’s are an extremely important part of shooting National Match games that can easily be worth a dozen or so points in a match. Even a very basic understanding of this concept early on in a shooter’s journey will pay dividends later on.
Above is an example of a shooter still struggling with this concept. Sure, many points were lost – but more detrimental is the confusion behind the lost points. Confusion like this can lead to doubt, which is not only unnecessary – but is the opposite of what shooters need to achieve their goals… CONFIDENCE! By looking at this sheet, chances are that all that is missing from the shooters skill set is a basic understanding of No-Wind-Zeros.
Establishing a good set of NWZ’s for a rifle can sometimes be a source of frustration of new shooters. Typically when starting out, shooters have had to rely on:
• one individual performance to the next, often with weeks in between
• confused wind reading abilities
• more experienced shooters who might shoot great, but not explain things very well
• voodoo, guesswork or giving up entirely!
Rest assured… Establishing solid & confident NWZ’s is relatively easy to accomplish!
First it is important to recognize that NWZ’s will change depending on certain factors: Ammunition (switching from one brand or load to another), elevation settings and shooting positions.
In simpler terms: each elevation setting of the rear sight and each shooting position used will generate a different NWZ. The shooter can only assume a NWZ based on a previous similar but unequal situation, and our goal is CONFIDENCE.
• a 200-yard Slow-Fire Standing windage setting will be different than a
• 200-yard Rapid Seated windage setting will be different than a
• 300-yard Rapid Prone windage setting will be different than a
• 600-yard Slow Prone windage setting.
(More on the WHY about this later… For now, let’s keep moving forward with what to do about it.)
THE TIME-OLD WAY TO APPROACH NO-WIND ZEROS:
Hopefully at a full-course match, shooters of every classification will be represented on the firing line. Soon after completion of the stage, politely ask the better shooters what they had on and average the responses. For example: if the answers are 2-minutes, 2 and a quarter minutes, 2-minutes & 1 and three quarter minutes – average out the high and the low = 2-minutes wind. Chances are that most of the better shooters on the line will have made a similar sight adjustment for the stage. Compare this call against the sight setting used (or what should have been used). The difference between this and MZ is the NWZ.
The new shooter will typically question a wind call before questioning equipment, but it is important to recognize that this shooter actually made a nearly perfect wind call. Many new shooters have made similar correct wind calls only to fall outside of the call due to a suspect NWZ.
Something obviously went wrong: the shooter’s call and NWZ are likely the culprits. Start with the known: 11-clicks right wind would have centered the group, therefore the correct wind call plus the right NWZ must equal 11 clicks right wind. Take what the better shooters have confirmed was the correct wind call, (6 clicks right) and subtract that from the known setting that would have centered the group (11 clicks right). The result is the proper NWZ (5 clicks right) in this position, at this range, with this combination of equipment. The shooter’s wind call was very close, and in fact would have netted a nice 99 or clean. The missing piece of the puzzle was the fact that the NWZ was assumed to be the same as a different position’s NWZ or a different distance’s NWZ. But now that it is known that the shooter’s NWZ was the major culprit, it can also be determined that the shooter’s wind reading ability is also fairly good. The shooter has new confidence, not only in the equipment but also in their ability to read wind.
AN EASIER ALTERNATIVE TO PROVE & ESTABLISH
CONFIDENT NO-WIND-ZEROS AT PRACTICE SESSION:
NO-WIND ZERO STRIP TEST:
This test is a process for a shooter to prove to himself what is mentioned above. It is also a fairly decent way to go about establishing NWZ’s if additional help isn’t always available.
The first thing required is a calibration target. This is a 100-yard MR1-C target with two-100 yard reduced targets flipped over and stapled above it, like the photo shown. Using a bubble level (or plumb bob) establish a vertical line from the center of the X ring on the MR1 C to the top of the two reversed centers. Place some 1″ tape extending along that line up through the reversed centers. Leveling the target frame prior to creating this vertical line will make this process easier.
The second thing required is some decent full-course elevation dope. These are the elevation sight settings that will get shots centered up and down on the target, from position – at 200, 300 & 600-yards. It is best if known elevations settings of that particular rifle are used, but basic “come-up’s” can also be applied if no solid elevation dope is available.
• up 2-minutes from 100y to 200y
• up 2 minutes from 200y to 300y
• up 10-minutes from 300y to 600y
From the appropriate position for each setting, shoot a 3 or 5-round group with only the elevation dialed for the according yard line. Be sure to use the same quality match ammo that is used for full-course matches (including 600-yard ammunition):
• 5-shots Prone w/ 100-yard elevation
• 5-shots Seated w/ 200-yard elevation
• 5-shots Prone w/ 300-yard elevation
• 5-shots Prone w/ 600-yard elevation
Most likely the point of impact for each elevation setting will appear outside of the ideal vertical strip. The goal is to have all of the shots appear inside the vertical strip, and to do so by adjusting windage on the rear sight. Recording these adjustments will give the shooter correct NWZ’s in each position at each elevation setting tested. In the example photo, it is clear that as elevation is added to the rear sight – shots land further and further right. Adjustments to the rear sight windage must be made to establish correct NWZ’s.
Measure the distance between the point of impact and the center of the 1″ tape for each elevation group. One minute of angle may be assumed to be 1″ at 100 yards for this test. Take these measurements and convert them to clicks depending on the click value of your rear sights (1/4-moa or 1/2-moa). In the example to the right, the 200 yard group is about 1″ away from the center of the tape, resulting in a corrected NWZ of 4L for 1/4moa sights at 200 yards.
The resulting NWZs,
to be recorded in the data book are:
• 100-yard NWZ: 6/0(MZ)
• 200-yard NWZ: 14/4L
• 300-yard NWZ: 34/7L
• 600-yard NWZ: 72/12L (* below for more info)
Once a solid NWZ has been established, the wind will seem less ominous. No more is the shooter wondering about such a bad wind call as described above. Now, when faced with wind – shooters can start to hone their reading abilities more securely AND successfully.
Known Zero is simply the known, current wind and elevations settings that are on the rifle. It is highly important that these are kept track of mentally or by plotting in a dope book. They are NOT additions to previous settings like “1 more” or “2 less” but full value numbers “5 clicks right from NWZ” or simply “5R”. During 600-yard slow-fire prone, these values become especially useful, giving the shooter a place of reference should conditions drop off or reverse completely.
* Addendum Regarding Excessive Clicking to NWZ at 600-Yards:
3-minutes worth of wind in either direction, as a determined NWZ is not uncommon – but on the larger side of comfortable. Should a shooter catch an extremely windy condition at 600-yards, this is now 3-minutes less windage available to put on in one direction (and is probably much more windage adjustment available than is necessary towards the other side…).
Future articles on this site will address the drifting of National Match windage-adjustable front sights. This is the process of getting your NWZ, with your chosen elevation – as close to mechanical zero as possible. The main take away is that a shooter really only wants the maximum windage travel at longer ranges. Short Line targets (100/200/300) require much less wind adjustment travel. Shooters opting to zero their own front sights would be served well to do so utilizing a strip test (as demonstrated above) to adjust the NWZ as close to MZ as possible, while dialed up with 600-yard elevation. This will ensure the greatest amount of windage travel is available at the distances it is needed. Most manufacturers, that zero their rifles before shipment to the customer – do so at 100-yards.