Re: HELP! Totally confused! Dope and Chrono disagree
My 2 Cents, mileage will vary,
Actual Dope vs. Computer Data
While a lot of shooters could care less about a Chronograph and Ballistics Program, I try to get the most out of them that I can. The “Old School” Data Book with Observed Results without a doubt has its place and value, but it doesn’t always work real well for all shooters and all situations. Using the Chrono and Ballistics program can take a lot of work to get good results, but once you get it figured out and working consistently, you can pull good data for about any situation that you find yourself in. Best option, is too use both of them together, no reason why you shouldn’t.
Getting the Chrono & Computer To Work
Unfortunately the saying $#!@ IN = $#!@ OUT applies here. Most situations where observed shooting results do not match the ballistic program output is because some of the data was entered incorrectly. The more data you input into the program, and the more accurate it is, the better the chance the computer data output will match the real world results. Some of the most common issues include:
Velocity – this number is obviously only as good as the Chrono that it comes from. Also have to remember that it can change based on the environment and shooting conditions.
Altitude vs. Altitude Density – it would probably take a couple of pages to fully explain “Altitude Density”, but if you do not understand the difference between the two then it is well worth the time to research it.
BC – it should go without saying that this number has to be as accurate as possible, but short of using Bryan Litz’s data, it can be very difficult to get an accurate number to use. BC is also velocity dependent, which can change the numbers greatly depending on any given set of circumstances. Using G1 vs G7 numbers can also have an impact.
Environmental Conditions – Temp and Humidity, along with the factors that dictate air density which ties into Altitude Density. Also something as simple as shooting with different wind conditions can have an impact not just on Windage but also on Elevation.
It should also probably be said that not all Computer Ballistic Programs are created equal. Whether it is the quality/accuracy of the software processing, or the amount of available input, some are simply going to be better than others.
I have found that when my observed shooting results are not matching the ballistic program output, I go back and start “tweaking” the input data until I get something that produces data that matches the actual results. It is usually pretty obvious after doing this, where my data input was off. After doing this a number of times, you will get better at making sure that your data input is more complete and accurate.
Additional Issues & Considerations
As pointed out by others in the material above, there are also other issues that can account for observed shooting results not matching the ballistic program output. A very common one is scope tracking issues. Ammo consistency/quality can also be a cause.
IMHO, if you do your part, and use quality instruments, then you should have no problem getting the observed shooting results to match the ballistic program output. It takes time, patience, and a lot of trial and error practice but it can be done accurately and consistently.
Sorry, not sure if any of this will help with this exact situation, but hopefully there is at least some general benefit out of it all.
Best of Luck,
M Richardson
