Normally when I dope a rifle out to distance I am shooting and then recording the data. After physically writing down the details I go back and set up the ballistic computers I use. This method helps me establish my dope quick and easy, after which I will true the computer with my real world data. Part of this method requires me to utilize my experience to know what starting Dope I need to hit the next target in line. Not everyone has that experience to fall back on so they immediately default to software to establish what I call "Try Dope" and its this we want to focus on.
As a disclaimer, I know everyone has their favorite Ballistic Solftware, there are a lot of Apps out there, most are relatively inexpensive. I am using Ballistics AE as I find it has a very robust library, and a good solid engine and UI to work with. It's probably one of the more common pieces of software. The process for any of the other apps is pretty simillar.
Ballsitic software needs some basic data to get started. Understand, with a limited amount of details you may find the need to "true" your software in order to match your real world results. The more actual data you use, the better your initial results will be, so it's important to keep and use your databook.
The Software cannot account for you, especially if you lack the proper fundamentals of marksmanship. The number one factor to effect the bullet is the shooter.
Using the Bullet Library
Ballistics AE has a great bullet library, this is important for the guy who is starting out with a new rifle and possibly a new caliber. We are advocating a lot of new shooters start out with the 6.5 Creedmoor so they may not have the details readily available.
The Bullet Library gives you several things, the Bullet Diameter, the Bullet Weight and most importantly for the Computer, the Ballistic Coeffecient.
Make sure you know what bullet your particular ammo brand is using. As an example, I am usng Winchester 6.5CM ammo, but the bullet being used is the 140gr Hornady BTHP. You will not find this information under Winchester, instead it's under Hornady. A lot of companies who load and sell ammo may use Sierra bullets, like Federal, so know the bullet manufacturer, not who loaded it.
The drag model is where a lot of people get into trouble. People read they need to use G7, but the software might not have the G7 value so it defaults to G1 which is readily available. So they will enter the library, pull the correct bullet which auto fills the data then they will go in and change the G1 model to G7. This completely starts you off on the wrong foot. Unless you specifically know you are using a G7 number (Which is usually smaller like .2** to .3** ) do not change the Native Drag Model. In my example I am using G1 because that is what is included in the library. G7 Data is limited so it might not be available.
Do not worry about using G1, it will work and really only starts to deviate from G7 after transonic ranges. In my case the Transonic range for my 6.5CM used in the video is just past 1750 yards. So does it really matter, no, and in so many cases the G1 models fits your real world results better.
More on that later...
Here is another point of guestimation. Not everyone owns a Chronograph, so for many they are guessing. I have to say, a lot of these guesses are flat out wrong. If you're serious about precision rifle shooting you'll invest in a chronograph. The MagnetoSpeed is not expensive, it's small and easy to use. I highly recommend one for the PR Shooter.
In the video I am using the Labradar, the personal Doppler device because I can just shoot like normal and record data. I recorded 14 shots over the Labradar in order to set up my software. This gives me a great starting average to work with. Muzzle velocity is one fo the places you can later tweak to true your computer. But the better real world data you have the less tweaking you need.
I have fired 47 shots across a chronograph and looking at the first 5 shot average and the last 5 shot average, the more the better.
If you wing this detail, you cannot expect miracles and the bullet to go where you want, especially farther out. This where you will have to shoot a target at distance and try to work the data backwards.
The next piece of data is also important for the software. The distance between the scope over the center of the bore, or Sight Height. The shooter should measure this distance using a ruler to determine how high the scope is over the bore, center to center.
In the video I said 3.0, but 2.5 is much closer to correct. So in the Ballistics AE Demo I used 2.5 vs what I did on the range.
Don't get wrapped around the axle here a simple course measurement is fine. No need to break out the calipers. Many use the gas port on the action to measure the distance to the center of the scope tube.
The distance to Chronograph should be noted, and in the case of the MagnetoSpeed and Labradar you have to change it from the default 10 ft to something much closer.
Again, don't change the Drag Model here next to muzzle velocity.
The Zero range should stay at 100 yards. Unless of course you are zeroed at something else.
From here you can change the range increments to something more practrical for your particular shooting. If your range only has targets every 100 yards, you can change it to that. Also I generally start my distance off at 200 yards as anything inside 100 yards is gonna be a hold over for mechanical offset. But changing these values will not negatively effect anything.
This is an important factor, you need real world data for this as well you need to know the difference between Barometric Pressure and Station Pressure or what the software calls Absolute.
Barometric Pressure is what your weatherman tells you on TV. It's adjusted for location and has to include the Altitude in order to explain to the software were you are in the world. It's based off 29.92 whcih is sea level.
For every 1000 ft in elevation you go up, like here in Denver I am at 5280, you lose about an inch of Barometric Pressure, so for me it would be 24.92. That becomes Station Pressure or Absolute. While it will work either way, the precision rifle shooter should use this.
I default to a Kestrel Weather Meter, and if you leave the unit set to the defaults from the factory, you will have Station Pressure. It also gives you the correct Density Altitude this way, so do not set it for your personal location but rather keep it set to sea level conditions so the meter can properly read the changes.
I normally don't advocate using the location services to pull this data, unless of course you have a solid internet connection at your range and you are close to an airport. It is possible for the phone to pull incomplete data or data from better than 50 miles away. It's best to use a weather meter and manually insert the data.
This is for the Zero Conditions, you would repeat this data for the Current Conditions. If you travel you leave the zero conditions and then change the current conditions so the computer knows how to adjust the dope for the new location.
If you use Absolute pressure make sure you check the box so it turns off the altitude. If you put in Station Pressure and also add in the Altitude the computer will double the value. So if you use 24.92 and also put in 5280 it will think you are at 10,000ft and not 5000ft.
For the Density Altitude guys, you can set it up to use DA. I never do, as I have the actual values in front of me. But the computer will just extract the original values from the DA number. In my opinion Density Altitude is a field expedient value used with DA drop charts and not with software. I record the DA so if I am going to a batteryless solution I have it. I print DA charts and laminate them.
I keep the Spin & Stability off by default, as well as Coriolis to start. If you are using Applied Ballistics I find you need to turn it on, if you are using any thing else not so much. Your mileage may vary, but I rarely start off using it. Understand to use it, you need to know the factors that effect it. For Coriolis you have to know your location in latitude and shoot an azimuth to the target. With spin you need the bullet length, twist rate, etc. But I find with software like Ballistics AE and JBM Online you don't need to worry about it and my data is usually closer to right then wrong. This mostly comes from the fact I shoot this stuff first so all that is included in my real world data so I have no need to add to something already in there.
Be sure to change your elevation units to whatever your scope adjusts with, and those numbers below are for truing. As you true your computers it's important to test tracking on your scope to find out if you need to adjust. This particular article is just for getting started, truing would come later.
Software is just a starting point until you true it. If you are a new shooter, you can almost guarantee the need to true everything, especially if you are not shooting it first collecting real world data.
Remember, back in the day, Manufacturer's Drop charts were designed to get you on a 6ft X 6ft target board, today we expect 1 inch accuracy which is unrealistic until you True.
Real World vs My Try Dope
The video says it all, but here are my real world numbers vs the Computer. This is just a start, I am going to head to the GAP Grind and actually shoot and record my data. Once there I will record everything including the local conditions and then make adjustments as necessary. But as you can see I was pretty close.
600 yards is super close, it's almost guaranteed to be right. In order to True this software the recommend picking a distance that is around 1300fps, for me, that would be almost 1500 yards away. So I would need real world drop at 1500 yards. Not everyone has access to that. So you are at the mercy of the software, it's bound to be an inch or two off.
200 Yards - .2
300 Yards - .9
400 Yards - 1.5
450 Yards - 1.8
500 Yards - 2.4
600 Yards - 3.2
Here is the Ballistics AE Data
Be sure the errors found between your real world data and computer data is not due to range. If you have not actually ranged your target, you risk have an odd unexplained error. Don't assume your local range has it right, check.
One note, you cannot dial the second decimal place, it's just there for rounding. So don't worry about the fact it takes you to two places when you can only dial one.
For More on Ballistics Calculators
The Sniper's Hide forum has a dedicated Ballistic Calculator Section so the users can ask questions and get answers. The Guys from Applied Ballistics are on hand to answer questions and also post some great informational articles.
One such article is about getting set up with a ballistic calculator, you can read it here to start off - Applied Ballistics Article for Getting Started
This is a journey, you have to do your part, but at the same time don't over think it.
Which every software you choose, read the manual, watch the videos and make sure you are not changing anything you are absolutely sure needs to be changed. Many of the default values will get you started.
Truing is a fact of life, we are only giving the software a limited amount of data, it cannot know everything. Until you true it's just Try Dope...
We are happy to help guys get up and running with software. Stop in and ask your question, you're sure to get real answer.