CHRONY TEST RECORD
Shooter: John SmithDate: 04/06/07
SHOT VelocityDeviation From
# ft/sAverage Velocity Test# M14-1 Cartridge: 223
13182H9Firearm: Mini-14
231721DATA
3316310Bullet/Weight: Jacketed SP/50 grains
431741Cast Alloy: NA B.C: .231
531807Case:RemingtonPrimer: Rem7-1/2
63160L13Powder/Weight:H-335/26 grs.
731763C.O.L: 2.235”
831694Crimp:Positive Crimp
931818OTHER:
1031730CONDITIONS
Total3173056Time:2 pm Temperature: 85F
Location:Cold Creek Conservation
Wind Direction: 2 o’clock
Wind Speed:5 MPH
EVALUATIONElevation:
High Velocity: 3182fps
Low Velocity: 3160fps
Total Velocities: 31730 fps SUMMARY
Average Velocity: 3173
Average Velocity =Total Velocities =3173 fps Extreme Spread: 22
10 Average Deviations: 5.6 fps
Sum of differences between each velocity & average velocity: 56 Energy: 1118 lbs
Sum of Differences = Average Deviation = 5.6 fps Distance of Chrony: 7ft
10 Standard Deviation: 7 fps
ENERGY CALCULATION: (ft-lb)
Average Velocity X Average Velocity X Weight of Bullet in grs. =1118 ft-lbs
450, 240
HOW TO USE THE CHRONY TEST RECORD
Above is a filled in CHRONY Test Record to show how to record your own tests and how to evaluate them. Below of this page is a CHRONY Test Record which is not filled in. We suggest that this Test Record being used to photocopy as needed, and stored for future use.
To prepare your Test Record follow these steps: Enter your name, the date, your own test reference number, the cartridge and firearm used. Under ‘DATA’ write down the make of the bullet and its weight. If it’s a cast bullet put down the percentage of lead, tin, etc. Write down the cartridge case, the primer used and how much (in grains), the cartridge length and the kind of crimp it has.
Under ‘CONDITIONS’ fill in the time of day, the temperature, the location, the wind direction and speed, plus the elevation.
Now you are ready to do the test shots. Mark the velocity of each shot as you go, starting at the top left corner with shot 1. When finished, pick the HIGHEST VELOCITY and write an H behind it; put an L behind the LOWEST VELOCITY.
Add up all velocities and divide them by the number of rounds; this will give you the AVERAGE VELOCITY. The EXTREME SPREAD is the difference in speed between the HIGH and LOW Velocities. Enter those values. Now that you know the AVERAGE VELOCITY, you can work out the deviation from the average velocity of every shot (write down in space provided). Add up these deviations and then divide this sum by the number of rounds and you will get the AVERAGE DEVIATION.
The ENERGY CALCULATION is again just a matter of following the formula at the bottom of the Test Record. We are also providing space to enter the STANDAR D EVIATION but how to compute it can be found in the CHRONY instruction manual.
CHRONY TEST RECORD
SHOT VELOCITY DEVIATION From Shootist:______Date:______
# fps Average Velocity
------Test #:______Cartridge:______
1 Firearm:______
------
2 CONDITIONS
------
3 Time:______Temperature______
------Location______
4 Wind – Direction______Shooting
------Speed______Direction______
5
------DATA
6
------Bullet/Weight:______
7 Cast Alloy:______
------Case:______Primer______
8 Powder/Weight:______
------Length of Cartridge:______
9 Crimp:______
------
10
TOTAL ______
EVALUATION SUMMARY
High Velocity =______fps AVERAGE VELOCITY:______
Low Velocity =______fps EXTREME SPREAD:______
EXTREME SPREAD = High –Low=______fps AVERAGE DEVIATIONS:______
Total Velocities:______fps ENERGY RANGE:______
STANDARD DEVIATION:______
AVERAGE VELOCITY = Total Velocity / n =______fps, where n is the number of shots
Sum of differences between each velocity & Average velocity:______
Sum of differences / n = AVERAGE DEVIATIONS =______fps, where n is the number of shots
ENERGY CALCULATION:
Average velocity X Average velocity X Weight of Bullet in grains/ 450,240 = ft.lbs.