Nightforce PC Ballistic Program
For years we never used a ballistics program or saw the need to buy one. After all, we were primarily hunters and didn’t need all the features of commercial programs. We used the Hodgdon’s Reloader’s Manual for all information pertaining to our reloads. It was relatively easy with a boresighter to get our bullets on paper at 100 yards and then “walk” the load into the bullseye with a few shots. That technique worked quite satisfactorily with factory ammunition as well as our own reloads. The few times that we wanted to determine the foot pounds of energy for our “pet loads” or determine bullet drop at various ranges, the free online ballistics programs were quite sufficient. Well, times change!
When our family started shooting in F-Class competition, we realized that a commercial ballistics program was necessary. All of the online ballistic programs had serious drawbacks. Most required you to obtain the ballistic coefficient of your bullets from external references. Furthermore, the majority had no provision for sight adjustment specifications, spin drift calculations, Coriolis Effect, or ballistic reticle analysis. Add in the problem of not being able to save your work with online programs, problems with printing out the results and you have a powerful argument for purchasing and using a commercial ballistic program. The Nightforce ballistic program covers all of the variables mentioned above and more. Although we use Nightforce scopes for target shooting, their program is not product-specific. It is a complete and thorough stand-alone ballistic program.
In the previous paragraph we mentioned the Coriolis Effect. Because of the earth's rotation, objects in both hemispheres rotate with the earth from west to east. An observer at the South Pole sees the earth as rotating clockwise based on an object located on a latitude line which is parallel to the equator. Likewise an observer at the North Pole sees the earth as rotating counter-clockwise.
There are three components to the Coriolis Effect which accounts for the apparent shift in the target position while a projectile is in flight. For rifle shooters we only need two components because we are not shooting directly away from the earth for great distances as would a missile for example. The horizontal component of this rotation results in a shift of impact point to the right (compared to line of sight) in the Northern hemisphere and to the left in the Southern hemisphere. There is also a vertical component which is caused as the target rises while it follows the arc of rotation. A due North (or South) will not have a vertical component but all other directions will have at least some Coriolis vertical component.
Under normal hunting conditions, the Coriolis Effect is minimal and can be ignored. At 600 yards, the effect becomes noticeable with a deviation of almost 1”. That value is now barely within the adjustment of scopes with 0.125 MOA /click, so it can also be ignored. At F-Class distances of 1,000 yards, it is something which must be taken into consideration.
The deflection increases as one approaches the earth’s poles. Hence, at 1,000 yards there is more deflection at Bisley in the United Kingdom (3.2”) with a latitude of 51oN than in Albuquerque, New Mexico (2.4”) with a latitude of 35oN. As such, being able to calculate the Coriolis Effect for all latitudes at which you may be shooting is a major benefit of the Nightforce program.
There is also a vertical deflection component to the Coriolis Effect. This is determined by the shooting direction in degrees from north. That value is calculated simultaneously with the windage deflection by the Nightforce program. However, there is a “problem” with the pull-down menu for calculation of the Coriolis Effect. It is for the northern hemisphere. It really isn’t much of a problem. A modification to the pull-down menu for the southern hemisphere has been prepared as I write this. In the meantime, I wrote to Gerald Perry (www.Perry-Systems.com) who developed the Nightforce Ballistic Program and licensed it to Nightforce for commercial distribution worldwide and he gave me the following information which will permit readers in the Southern Hemisphere to use the existing menu. Input your latitude and shooting direction (Azimuth - degrees from north) and the deflection values will be correct. You simply interpret the horizontal deflection as left, rather than right. The vertical components are unchanged. Up is up and down is down.
Should you even bother to consider factoring in the Coriolis Effect? We could probably find just as many shooters who choose to ignore it as those who want it calculated. The same discussion could be had in reference to spin drift. The bottom line is, we can’t settle the argument, but the availability of the calculations are there if you want them.
All ballistic programs assume that you have sighted your rifle in at a fixed distance. Most hunters pick 200 yards, so that they can “ignore” drop and hold dead on up to 250+ yards. However, target shooters need more accuracy, so they generally sight in at 200 yards and calculate the drop adjustment in MOA for distances out to 1,000 yards. In that way, knowing the specifics of their scopes, they can literally dial in the corrections for distance and hold on target. That beats the heck out of trying to estimate how high to hold above the bullseye.
To insure a more thorough analysis of this program, we sought additional input from other users. We wrote to competition shooters in Ireland, the United Kingdom, South Africa and the United States to obtain their views on the Nightforce ballistic program. They are all world-class shooters who have been using the program at least two years. Their remarks can be summed up in a few sentences.
From Ireland: “If you input the correct velocity and sight height above the bore, you will be plus or minus one minute at 1,000 yards.”
From South Africa: “Whether you are a big game hunter or target shooter, it is the most complete ballistic program on the market and well worth the price.”
From the United Kingdom: “It saves time and ammunition at the range. I often wonder how I managed without it.”
From the United States: “Make sure you take your laptop to every practice and competition, as this program can turn your shooting into a trigger pull.”
We put the Nightforce program to a test at 600 yards. We input data for our daughter’s 6BR load, which was sighted in at 200 yards:
Susannah dialed in an elevation adjustment of +10.50 MOA for 600 yards. She added 0.25 MOA to both her vertical and windage adjustments to compensate for Coriolis. Three rounds fired and the group was tight and consistent at about 2” low and slightly to the right (in the 10-ring). We took a brief coffee break (got to have my coffee) and repeated the test. Three more rounds fired with almost the same group as the first time. That kind of accuracy from a ballistics program is incredible. We both are comfortable in stating that the Nightforce program is just as good as shooters from across the globe told us it would be. It may not turn your shooting into a “trigger pull”, but the program will definitely give you a competitive advantage. Add the fact that you can order versions for either your computer or PDA and you have an incredibly versatile piece of user friendly software.
And of course, as with all ballistic computer programs, the results are only as good as the data you input and represent a starting point for your individual equipment. If properly used, the Nightforce program will save a lot of ammo, wear and tear on the barrel and frustration of trying to bring the rounds into center of the target.
The following is a list of calculations and references available in the Nightforce ballistic program (excerpted from Nightforce ballistic program brochure):
· Option to use Metric System units
· Formulates zero-point solutions to hit long range targets
· Records and recalls sight-in data
· Profiles of rifle/ammunition/atmospheric condition scenarios
· Performs all necessary calculations for ranging reticles
· Calculates corrections in M.O.A., I.P.H.Y., Mils and C.P.H.M.
· Prints reference cards, plots graphs and drop charts
· Library of more than 500 ballistic coefficients
· Exports data to Excel spreadsheets
· Comprehensive manufactured ammunition database
At a 2008 MSRP of $69.99, the Nightforce program will pay for itself very quickly if you are a varmint or target shooter. If you are a hunter, it will provide you with the assurance that your rounds will be on target when you finally get that trophy-of-a-lifetime in your sights.
We spend a lot of money on our rifles, scopes and ammunition, not to mention the costs of our hunting trips. It just makes sense to spend a bit more to increase our chances of success. If you don’t have this program, buy it. We guarantee that you won’t regret the purchase.
Our sincere thanks to Gerald Perry for his advice and suggestions during the preparation of this article.
Copyright 2008 by Jim Clary. All rights reserved.