As the title reveals Ballistic Calculators are not reliable. Here is how the US Army and the Army Materials Systems Analysis Activity performs such.
When I got to Aberdeen Proving Ground I linked up with a guy in BRL (Ballistic Research Lab) and he told me that down range performance duplicates ballistic calculations 5% of the time. For instance the projected bullet drops might be dead on at 300 and 800 meters but nowhere else.
To be sure the ranges at Aberdeen are about three feet above sea level so there is no deviations from elevation of different ranges.
Now that being said if you get data in US Army Manuals you can be assured it was developed from actual testing at Aberdeen as follows:
We have two longer distance ranges at Aberdeen and one went to 1500 yards and one went to 2500 yards. The one at 2500 yards at first look you think is a drive in cinema screen placed at the end of a one lane road perfectly straight. It is 32 feet high and 32 feet wide and has plywood covering entire face and over that is placed white target cloth that is six feet wide.
Three rifles are selected out of ten and the one with the worst dispersion capability , the one with the median dispersion capability and the one with the smallest dispersion capability are fired after they are zeroed to deliver POA/POI at 100 yards on a indoor range AND THE SIGHTS ARE NEVER TOUCHED AGAIN.
Only NRA Certified Master Class shooters are used to conduct this testing and can be left or right hand shooters.
A target is placed on the board and a string bob is used to establish a vertical line through the target and a line with permanent ink is made extending below the target for the appropriate drop distance below the aiming point.
Another horizontal line is placed across the board that intersects the vertical line at the 6 o'clock position on the target. This gives four quadrants.
At the closest range the target is plotted every ten shots as follows:
Shots in the top left quadrant are classified as +/-, the top right quadrant is +/+, the bottom left quadrant is -/- and the bottom right quadrant is -/+. The plumb bob is used and the shot is measured to the closest millimeter to center of hole from the horizontal line and the vertical line and recorded on a form at each range. 3 ten shot groups are fired by each firer with each of the three weapons separately.
All this data is fed into a computer and the computer will reproduce the shot groups for each ten shot string and calculate the bullet drops, the extreme spread of each ten shot group and then compiled in a massive target and the average groups and ballistic drops for all three weapons are calculated both individually and collectively.
The same lot number of ammunition certified to meet dispersion acceptance requirements by the test center before it leaves the production facility. For 5.56 it is done at 200 yards, for 7.62-50 cal is done at 600 yards.
Bottom line is 90 rounds from each shooter is plotted and computer prints out actual impact dispersions and no projections are used. Then the Firing Tables are published showing the average of all thee rifles from all shooters is published. So at a min you have 180 shot data base or a 270 round data base hard data record for each yard/meter line as the testing calls for.
I was the "Control Shooter" on the M16A1E1 Test (adopted as M16A2 by USMC and US Army) as the analytical people wanted to make sure the same person fired all targets with all weapons with the same sight settings.
In short we were just looking for dispersion data and not a score.
Obviously as the range increased the target was raised and a guy in a bucket would hold the plumb bob for the vertical shots and a 5 ft certified level was used to plot the shots left and right of the vertical line.
After that test I was requested to conduct the same testing on the first AK74 we got in the states in 82 and the Army Materials Systems Analysis Agency (AMSAA) had the rifle and wanted the same control shooter. I was told it was to be exactly as I had conducted the M16A1E1 Series and the same range, target, time of day was duplicated down to the same range crew was used to plot the targets.
This was classified so tight it was not given a code name and I could not discuss it until 2015 when I was released as the AMSAA analyst did not publish data admitting we even had it until 1986 and there were two more done. Only the last one was released and the original was never released and the last one authored by same analyst is available on internet. The testing was conducted on the weekends when the Proving Ground was closed.
If anyone is interested I have pictures of the AK74 testing being conducted with me firing.
When I got to Aberdeen Proving Ground I linked up with a guy in BRL (Ballistic Research Lab) and he told me that down range performance duplicates ballistic calculations 5% of the time. For instance the projected bullet drops might be dead on at 300 and 800 meters but nowhere else.
To be sure the ranges at Aberdeen are about three feet above sea level so there is no deviations from elevation of different ranges.
Now that being said if you get data in US Army Manuals you can be assured it was developed from actual testing at Aberdeen as follows:
We have two longer distance ranges at Aberdeen and one went to 1500 yards and one went to 2500 yards. The one at 2500 yards at first look you think is a drive in cinema screen placed at the end of a one lane road perfectly straight. It is 32 feet high and 32 feet wide and has plywood covering entire face and over that is placed white target cloth that is six feet wide.
Three rifles are selected out of ten and the one with the worst dispersion capability , the one with the median dispersion capability and the one with the smallest dispersion capability are fired after they are zeroed to deliver POA/POI at 100 yards on a indoor range AND THE SIGHTS ARE NEVER TOUCHED AGAIN.
Only NRA Certified Master Class shooters are used to conduct this testing and can be left or right hand shooters.
A target is placed on the board and a string bob is used to establish a vertical line through the target and a line with permanent ink is made extending below the target for the appropriate drop distance below the aiming point.
Another horizontal line is placed across the board that intersects the vertical line at the 6 o'clock position on the target. This gives four quadrants.
At the closest range the target is plotted every ten shots as follows:
Shots in the top left quadrant are classified as +/-, the top right quadrant is +/+, the bottom left quadrant is -/- and the bottom right quadrant is -/+. The plumb bob is used and the shot is measured to the closest millimeter to center of hole from the horizontal line and the vertical line and recorded on a form at each range. 3 ten shot groups are fired by each firer with each of the three weapons separately.
All this data is fed into a computer and the computer will reproduce the shot groups for each ten shot string and calculate the bullet drops, the extreme spread of each ten shot group and then compiled in a massive target and the average groups and ballistic drops for all three weapons are calculated both individually and collectively.
The same lot number of ammunition certified to meet dispersion acceptance requirements by the test center before it leaves the production facility. For 5.56 it is done at 200 yards, for 7.62-50 cal is done at 600 yards.
Bottom line is 90 rounds from each shooter is plotted and computer prints out actual impact dispersions and no projections are used. Then the Firing Tables are published showing the average of all thee rifles from all shooters is published. So at a min you have 180 shot data base or a 270 round data base hard data record for each yard/meter line as the testing calls for.
I was the "Control Shooter" on the M16A1E1 Test (adopted as M16A2 by USMC and US Army) as the analytical people wanted to make sure the same person fired all targets with all weapons with the same sight settings.
In short we were just looking for dispersion data and not a score.
Obviously as the range increased the target was raised and a guy in a bucket would hold the plumb bob for the vertical shots and a 5 ft certified level was used to plot the shots left and right of the vertical line.
After that test I was requested to conduct the same testing on the first AK74 we got in the states in 82 and the Army Materials Systems Analysis Agency (AMSAA) had the rifle and wanted the same control shooter. I was told it was to be exactly as I had conducted the M16A1E1 Series and the same range, target, time of day was duplicated down to the same range crew was used to plot the targets.
This was classified so tight it was not given a code name and I could not discuss it until 2015 when I was released as the AMSAA analyst did not publish data admitting we even had it until 1986 and there were two more done. Only the last one was released and the original was never released and the last one authored by same analyst is available on internet. The testing was conducted on the weekends when the Proving Ground was closed.
If anyone is interested I have pictures of the AK74 testing being conducted with me firing.
