FOR THE SHOOTING CHRONY® CHRONOGRAPHS,
MODELS: ALPHA SHOOTING CHRONY® and ALPHA MASTER CHRONY®
(** Please Read These Instructions Carefully
Before Using The Chronograph)
SHOOTING CHRONY INC. assumes
no responsibility, either directly or indirectly, for any action or
consequences of any actions associated with the use of its products.
Chrony® measures the speed of bullets, arrow, shotgun-pellets,
airgun-pellets and paintballs, etc.- from 30/FPS (feet per second) to
7000/FPS and with better than 99.5% accuracy. Your Chrony will go with
you anywhere. Just unfold, mount on a tripod or place on a table, insert
Diffusers (if needed) and shoot in less than 2 minutes. All Chronys
come with a 3 year limited Warranty. The Master Chronys
have the same capabilities as their respective Shooting
Chrony counterparts. In addition to that, the Master
Chronys have a LCD Monitor which brings the LCD (Liquid
Crystal Display) readout right up
to your bench, away from the bullets path. It also doubles as a Remote
|Table of Contents
|Retrieve Statistics (Hi,
Lo, Average, etc.)
|Remove A Single Shot
|Remove All Content From Memory
|Change From FPS To MPS Or Vice
|Turn Sensors OFF/ON
|How It Works
|Rifles, Handguns, Shotguns, Muzzle
|Turn Unit On
|What You See On Press
|Delete Single Shot
|Start New String
|Tips & Hints
|How To Turn Off Sensors
|Formulas (Standard Deviation,
Energy calculation, etc.)
|Glossary of Display Codes
|Company Address, Phone, Fax,
FEATURES of the ALPHA and ALPHA MASTER
If it doesn’t unfold, it’s not a
Fig. 1. Closed Chrony.
Numbered Shot Velocities; + Velocity stays on display until you shoot
again; + Uses 9 Volt Alkaline Battery with 48 hours of continuous
use; + With flip of finger switch from FPS (feet per second) to MPS
(meter per second); + Delivers Measurements and Statistics such as:
High, Low and Average Velocities, Extreme Spread and Standard Deviation;
+ Retrieve individual Shot Velocities and Statistics; + Has 32 shot
memory; + Delete individual shots (with automatic adjustment of Statistics);
+ Has Stereo Jack for optional Ballistic Chrony Printer
or Remote Control; + Accepts Timer
Mode option; Can be upgraded to Beta and
Gamma Shooting Chronys and respective Master
HOW IT WORKS
The Chrony has two eyes (or photo
sensors) located in each of the black plastic housings at the front and
back of the main unit. They are located under the Twin Lenses at the bottom
of these housings and they detect the passage of a bullet over them by
sensing the change in the amount of light. (They detect a momentary change
in light intensity.) As the bullet passes over the first detector, it
trips a counter, which begins to count very rapidly (much as a super-fast
stop watch). The counter is shut off by the second photo sensor when the
bullet passes over it. The computer in the Chrony then converts this information
into feet per second (FPS) or metres per second (MPS), whichever mode
it is operating in.
After the first shot, it computes all
statistical information, such as Hi((gh), Lo(w),
Av(erage) velocities, Extreme Spread and Standard Deviation,
following each new shot.
The Alpha Chrony has a temporary
(working) memory. This allows the erasing of part or all of the data stored.
Only the Beta, Gamma, Beta Master and Gamma Master Chrony
units have a permanent memory, which allows the unit to be turned off
without losing data.
THE BEST WAY TO LEARN TO USE THE SHOOTING CHRONY
It is not necessary to understand all the functions of the instrument
immediately. It is best to proceed slowly, safely and have fun doing it.
Getting the Chrony ready to use:
- First, unfold the unit, making certain that the unit
is FULLY OPEN. The base of a tripod may prevent full opening, in which
case the chronograph will read higher (faster) than true velocities
because the space between the points where the bullet crosses the photocells
is shorter than is the distance for which the unit is calibrated.
- Attach a 9 Volt Alkaline
Battery to the short cable inside the front housing and
tuck it under the spring. If it is not Alkaline, the Chrony may not
work properly. With a standard model Chrony, the unit is ready to turn
on with the switch on the face. With a Master Chrony model, attach the
long telephone cable into the LCD (Liquid Crystal Display) Monitor and
to the inside terminal of the front black sensor housing of the unit.
Do not drag plugs ( at the ends of Master Chrony cable) on the ground.
If sand particles get stuck between the leads, Chrony will malfunction
. It is now ready to be turned ON.
Steps on Setup at the Range.
- The first step is to ensure a safe backstop.
A chronograph should never be used without a safe and certain backstop
that stops the projectiles (bullets, shot, arrows), and prevents ricochets.
- To safeguard the Chrony and to prevent missing
the backstop, any firearm used must be fired from a good rest. A bench
with sandbags is the best type of rest.
- For the best use of chronographs, velocity measurements
should be combined with target shooting (that is, you are chronographing
the same bullets that are being shot at the targets). Set up a suitable
target against the backstop.
- To safeguard the instrument (and to obtain the best
results), the projectile must pass between 6 and 4 inches (15 and 10
cm) directly OVER the Twin Lenses in the black plastic boxes at the
front and back of the chronograph. These are the chronograph’s
"eyes". Attaching pieces of dark-coloured tape on the guide
rods (wire rods) at these heights will help you to aim your shots accurately.
- THE SHOOTING AREA
| Every Shooting Chrony and Master
Chrony comes equipped with an adjustable-size, triangular shooting
area (actually an upside down trapezium) from 8" X 8" to
14.5" X 14.5" (Fig. 2). All Chronys come equipped with four
9.25" wire rods as well as four 6.5" wire rods with brass
connectors attached. The 9.25" wire rods are to be inserted at
an angle into the outer holes visible on the black plastic boxes of
the unit. On bright, sunny (blue sky) days, install the white plastic
diffusers on top of the wire rods (to simulate clouds). The
photo-sensors are pointed at the diffusers, which create a white background.
The diffusers provide a good contrast between the bullet and the background
(clouds or diffusers). On cloudy days, use the wire rods
for alignment but without diffusers.
Fig. 2. Shooting Chrony, front view
should be at least 10 feet (3 m) from the muzzle of high-powered rifles,
but can be closer to guns with a lesser blast. Five feet (1.5 m) is
about right for .22 rimfire firearms. Shotguns should be fired at
5 feet because of possible damage caused by the spreading pattern
of the shot and errant wads.
|9. The Chrony may be mounted
on a (camera) tripod, or on any adjustable device, having a 1/4 inch
by 20 thread that will screw into the hole on the bottom of the unit.
It is also possible to rest the Chrony on a table, though this is
probably the most difficult type of mounting to adjust properly.
|10. With an Alpha
Master Chrony place the LCD Monitor near you on the bench, well away
from muzzle blast
|11. Have a notebook and pen with you
to record your results and to make notes.
|12. ALWAYS WEAR EYE AND EAR PROTECTION
STOP! BEFORE YOU FIRE THAT
|A. Be Sure that the
backstop is adequate.
RIFLES: Be aware that the bullet line of travel
will be as much as two inches BELOW the line of sight on scope-sighted
rifles. Adjust upward in order NOT to hit the Chrony. If
a bullet hits the Chrony, the Chrony will be destroyed, and will endanger
you and others because of bullet ricochet and flying parts of the
Chrony. Mark the Wire Rods with tape four inches above the Chrony
unit for open-sighted rifles, and six inches for scope-mounted rifles.
Fig.4. Protective Shields
When shooting sub-sonic ammo, the muzzle blast will get to the Chrony
before the bullet, which may cause erratic numbers. Increase distance
because flying wads may go in any direction, protect the face of the
Chrony by taping a thick piece of clear acrylic over the front of
the unit. The acrylic must not extend above the face. Shooting Chrony
Inc. offers such protection (see Accessories List). NOTE: When shooting
without Diffusers one may substitute soda straws or wooden dowels
for the Wire Rods. Hitting the Wire Rods with a bullet could break
the Sensor Housings, whereas straws and dowels provide a safer sighting
LOADERS AND OTHER BLACK POWDER FIREARMS: In addition
to protecting the face of the Chrony from wads and patches, you may
cover the slots (eyes) of the photo sensors with strong and clear
tape or Protective Shields (Fig.4) to prevent powder residue from
entering these slots. Glass or clear plastic taped over these slots
may also be used.
ARCHERY: Bow to
Chrony distance should be at least an Arrow’s length. Blunt-tipped
or flat-tipped arrows give more Accurate velocity measurements.
O.K., NOW YOU ARE READY
Until you are familiar with the Chrony, shoot
inexpensive ammo, such as airgun-pellets or .22 rimfire bullets. Doing
so will save you money.
UNIT ON. If you purchased the Chrony in the United
States, it will automatically record and read in feet per second (FPS).
If you purchased it in a country that uses the metric system, it will
record and read in metres per second (MPS).
- An Alpha Chrony will display AL with
flashing symbols on each side. These flashing symbols indicate that
the unit is working and is ready for use. For Chronys that are set to
read in MPS, it will display a dot between the two letters (e.g.,A.L),
with the same flashing symbols on each side; without the dot (e.g.,
AL), the unit readout is in FPS.
- The Alpha Chrony has a working memory for up to 32
shots; it has no permanent memory. As you fire each shot, the LCD will
display the shot number briefly and then the actual velocity of that
shot. When you have fired 32 shots, it will display the number 32 and
then the velocity. The 32nd shot will alternately flash with =LN=,
which means that the memory is full. LN actually stands
for LiNear mode. If you keep shooting,
the first shot will be replaced by the next shot you fire. The display
will flash =SO=, telling you that you lost the first shot and, had it
replaced by the last shot.
Fig.4. Master Chrony
|The Alpha Chrony
will provide you with summary data such as HI, LO, Average
and the total number of shots fired, plus Extreme Spread,
Standard Deviation as well as numbered shots and retrieval
of individual shot velocities.
To delete an existing string for any reason, or to start a new
a)Turn the Alpha Chrony OFF, and then
b) If you have the Remote Control (and
you don’t want to get up), see page 5, under "How to
delete Chrony memory."
- If you now turn the Alpha OFF,
you will lose your data. It has TEMPORARY (working) MEMORY only.
- Anytime you wish, you may view the data you have produced.
To do this, simply press the (left, black) FU button,
identify the information you are about to receive, release it and read
each individual piece of information. Repeat this process for each piece
of information shown in the table below:
|What you see on press
||What it means
||What you see on release
||Will always be #1 with the F-1 Chrony;
||velocity of the slowest shot
||velocity of the fastest shot
||Average velocity of all shots
||Hi velocity minus Lo velocity
||Standard deviation of string of shots
|Total number of shots recorded since Chrony was
||The number of shots fired.
|# of last shot fired
||velocity of 10th shot
| # of next to last shot fired
||velocity of 9th shot
etc., etc., repeat until all the shots have been shown,
then -[ ]- appears. This means the end of the data and,
that you are ready to shoot again. If you press the FU
button again, you start the viewing cycle over again. Simply pressing
and releasing the FU button takes you from one piece
of data to the next.. If you wish at any time during the viewing process
to return to the working mode, stop pressing the button and wait 15 seconds.
It returns to the working mode by itself. Sometimes, if you hold the FU
button down for more than two seconds at a time, the unit will go into
a sub-menu. Wait 15 seconds, it will return to normal by itself. When
you think that you may have done something wrong, take your hands off,
and it will go back to normal by itself. Features like this make the Chrony
very forgiving and easy to use.
On the left-hand side near the front of the Alpha Chrony
is a Stereo Jack that will accept a 16' (5 m) cord for the optional one-button
Remote Control. This Remote Control
lets you access all Alpha functions from the shooting bench. The Stereo
Jack also accepts the IBM/PC Interface patch-cord
or the Chrony Ballistic Printer. Please note:
The Remote Control is an optional accessory
and available from SHOOTING CHRONY INC. direct only. The Push Button on
the Remote Control activates the FU
functions. If you have a Chrony Ballistic Printer,
it will also function as a Remote Control.
Opposite the FU button a Timer Button can be
factory installed as an option. This button will convert the Chrony
into a Timer/chronograph. Press & release
the Timer Button and the Chrony will
be in Timer Mode. When in this mode, all symbols
are flanked by horizontal double bars such as =[ ]=,
etc.; The Timer is shot-activated, not sound-activated.
The first shot triggers the Timer to count the time between shots, as
well as the total time between the first and the last shot. When done
shooting, use the FU button to retrieve the Timer
Statistics and Time elapsed between
shots. Whether in Timer Mode or Velocity
Mode ,both: Time and Velocity are recorded and stored in
working memory. The difference is: When in Timer Mode, only Time is displayed
and, when in Velocity Mode, only Velocity is displayed.
When chronographing velocity readings of less than 1000
FPS, the readout will display a Decimal Point and tenths or tenths and
hundreds as fir instance: 985.7 FPS or 43.69 FPS, etc.;
This chapter will deal with other (commonly needed and
useful) functions. It does not deal with advanced functions.
Let us say that you brought two different loads of ten rounds each to
test (20 rounds in total).
You could contaminate or ruin your data in one of two
- You might forget to start a new string when changing
your load after any number of shots; or,
- You might fire 32 of one kind, then change the load
and continue firing, ignoring the flashing Ln or Ci. When you do this,
you replace existing data with new data, thus mixing data together in
the string. In addition to mistakes you might make, errant data sometimes
occur for reasons that are difficult to identify. Powerlines, accidental
shadows, and other phenomena may cause a wild velocity reading to appear.
Such things are uncommon, but must be rectified if they do occur.
In order to "clean up the data", you must know
how to remove the unwanted shots contaminating your string of data.
HOW TO DELETE CHRONY
DELETING DATA WHILE IN OPERATIONAL MODE:
- Deleting Single Shot:
Press and release the FU button repeatedly until the desired shot number
is displayed (NOT the velocity). Press and hold the FU button until
display flashes. Release immediately when it flashes.
- Starting a new String:
Turn the Alpha Chrony OFF then ON, or: Press and release the
FU button until -Hi- is displayed. Hold the
button in until the display changes to -CL-, then release
the button. -Clr- is now displayed. Press and release
the left FU button until the display changes to -CLS-,
then press and hold the FU button in until the display
flashes. Release immediately when it flashes.
FROM FACTORY DEFAULT FPS to MPS
or VICE VERSA
Turn unit OFF. Press and hold
FU button while turning unit ON.
Release button. If you now turn the Chrony OFF and then ON again, the
readout will be as it was, when set at the factory.
To save the alternate setting as a permanent setting, press and release
the FU button until you see ES
and hold down until the message changes to EP,
then release the button. After releasing Button LEN
will be displayed. Press and release one more time and SSE
will be displayed. Press and hold until SSE
flashes, then release immediately. Now you have changed the setting permanently.
Fig.5. Indoor Shooting Lights
|For proper functioning, a Light-Diffuser
and an incandescent light source must be located above each photo-sensor
(Fig. 5). The optional Indoor Shooting Light Fixture
enables Chrony users to pursue indoor use. It works on 115 V house
current and overpowers any other light in the same room. Neon or other
fluorescent lights cannot be used as a Chronograph light source, because
they flicker at twice the AC (alternating current) power frequency,
and cause false readings.
|SO FAR: You have learned
to set up and operate the Chrony safely. You have learned
how to record data, how to retrieve data, how to clear an individual
shot and a string of shots. During the operation, you may encounter
symbols or problems not yet explained. They may include the following:
A) PROBLEM: =Lb=flashing. Cause & Remedy:
Battery is low and must be replaced.
B) PROBLEM: No LCD display. Cause & Remedy:
- No battery: connect battery;
- Unit is not turned on; turn unit -ON-;
- Bad connection: tighten battery snaps;
- Battery is dead: replace battery;
- Battery NOT Alkaline: replace with ALKALINE battery.
C) PROBLEM: No reading after shooting. Cause &
- not using diffusers on blue sky, sunny day; add diffusers;
- using diffusers on a cloudy day; remove diffusers;
- unit too close to muzzle; move unit farther away;
- not shooting directly over photocells; aim more carefully;
- unit not properly aligned with bullet path; realign
rifle to point directly at target; and,
- shooting too early or too late (poor light conditions);
wait for better light, or end chronographing session.
D) Err 1 shows on screen; the first sensor
did not detect the passage of the bullet. This means either that the shot
was not fired directly over the centre of the first sensor, or, that there
are poor light conditions. Be sure that the Chrony is aligned with the
line of fire.
E) Err 2 shows on screen; the second
sensor did not detect the passage of the bullet. Same as above: poor light
or poor alignment.
F) Err 3 through Err 9 shows
on screen; the exact number relates to internal codes, and is of no significance
to the user. May indicate poor light condition. Installation of Diffusers
G) Low velocity reading. Light conditions
not right; try diffusers. You may be shooting during poor light conditions.
H) False reading (usually high); can
result from very strong light, or by operation near electric motors, radar,
powerlines, electric fences, static electricity, radio transmitters, etc.
It may also be caused by the Chrony being too close to the gun’s
muzzle. Remedy: try using diffuser, moving away from electrical interference,
moving unit farther from the muzzle, or all of these.
I) Very high velocity readings: 1)
can result from muzzle blast; move Chrony farther from muzzle; 2)
Chrony is not fully open; check for interference from tripod or base.
J) Dead display in cold weather; replace
battery with a warm battery.
OTHER TIPS AND HINTS
Make allowances for temperature differences between chronographing
your loads and their use in competition. In cold weather, powders burn
more slowly and will produce lower velocities than they will at higher
temperatures. Different altitudes may also affect velocity. Loads developed
which are near maximum velocity during cold weather may produce dangerously
high pressures and be unsafe during hot weather. Always try to match conditions
while chronographing with those conditions you will face when shooting
or hunting. That is, if you hunt in late autumn, do the chronographing
in late fall.
ALWAYS WEAR EYE AND EAR PROTECTION
On sunny days, at certain angles, light may reflect from
the bullet and cancel the bullet’s shadow. Mark the bullets all
the way around with a dark-coloured felt marker if this seems to be happening.
On sunny days, the Chrony may be tilted sideways toward
the sun, so that the Diffusers are between the sun and the photocells.
Be sure that the Chrony unit remains fully open, and that it is perfectly
aligned with the target. Using diffusers on cloudy days may shut out too
Using diffusers on cloudy days is not necessary, since
you have the clouds as a white background for contrast.
HOW TO TURN OFF PHOTO SENSORS
Turn Chrony off. Press & hold ST button while
turning Chrony on. Release button.
SENSORS disable/enable while in operational
Press and release left button until -Av- displays; hold
the left button until -SE- displays, release button and
=FE= or =ME= will display. Press and release the left
button. When =ON= displays, press and hold the left button
until the display begins to flash, then release immediately. (The Screen
is disabled.) When =OF= displays, press and hold the
left button until the display flashes =ON= to enable
the screen again.
Your Chrony calculates data similar to formulas shown below:
Average (Mean) Velocity
||Where V is velocity and n is the number
|Total all shots in a string
and divide by the number of shots in the string,
e.g., (2990 + 3010 + 2996 + 3004) ÷ 4 = 3000 FPS
Deviation, population, (-Sd-)
Multiply the square
of the average velocity by the number of shots and deduct it from
the sum of the squares of all shot velocities, then divide this
total by the number of shots minus 1, and then take the square root
of this figure.
For example: [(29902 + 30102 +29962 + 30042 - 4 x 30002)
÷ (4-1)]½= 9 FPS
Standard Deviation is a measure of how close each
shot’s velocity will be to the "average" shot. It
is called STANDARD because it is computed in such a way that it
has a standard meaning when compared to the NORMAL CURVE. Nearly
all things we measure fit a normal curve [such as the height of
people, the diameter of (supposedly) identical motor pistons, and
the velocity of (supposedly) identical cartridges]. The NORMAL CURVE
shows that all variables occur more frequently at or near the average,
and less frequently as they deviate further from the average. We
use a STANDARD Deviation measure so that all things we measure can
be compared with each other and to this curve [68% of all things
we measure falls between one standard deviation above or below average,
95.4% falls between two Standard Deviations above and below the
average, and 99.7% falls between three Standard Deviations above
and below the average]. Thus, Standard Deviation is a universal
method in statistics and measurement for dealing with and interpreting
Therefore, if the bullets are traveling at an average
velocity of 3000 feet per second, and there is a Standard Deviation
of 20, then 68% of the shots you fire will fall between 2980 and
3020 fps, and 95.4% will fall between 2960 and 3040 fps. Nearly
all of them (99.7%) will fall between 2940 and 3060 fps.
Since Standard Deviation is the most important information
your chronograph can give you, it is useful to understand the reason
for this. At least ten (10) shots are required to obtain a reliable
average and Standard Deviation. Fewer shots (such as 3 or 5) are
typically "small samples", and are considered unreliable
when measuring anything variable.
||Hi - Lo
|Subtract the slowest shot
from the fastest. For example: 3010 - 2990 = 20 FPS
velocity X Average velocity X Weight
of bullet in grains ÷ 450 240 = _____ft. lbs.
GLOSSARY OF DISPLAY CODES
|FROM OPERATIONAL MODE
|or other #. REPRESENTS A RECORDED SHOT’S
|LOWEST VELOCITY SHOT OF ACTIVE STRING
|HIGHEST VELOCITY SHOT OF ACTIVE STRING
|AVERAGE VELOCITY OF ALL SHOTS IN ACTIVE STRING
|EXTREME SPREAD FOR ACTIVE STRING (-Hi- minus
|STANDARD DEVIATION FOR ACTIVE STRING (STATISTICAL
MEASURE OF UNIFORMITY)
|TOTAL NUMBER OF SHOTS RECORDED SINCE CHRONY WAS LAST
|(Used in this manual to represent an unspecified
|(Used in this manual to represent an unspecified
shot number 1 less than previously displayed shot number)
|END OF MENU AND READY STATE (UNIT IS IN OPERATIONAL
MODE/READY TO ACCEPT DATA)
|UNIT IS IN FPS DISPLAY MODE
|UNIT IS IN MPS DISPLAY MODE
The Chrony reads velocity in feet-per-second
(or metres-per-second) and works in a velocity range from 30 fps to 7000
fps (10 mps to 2134 mps). Operating Temperature range: 32o Fahrenheit
to 110 o Fahrenheit (0 o Celsius to 43 o Celsius), non-condensing. (Ambient
temperature must be above dew-point temperature and not fall below dew-point
temperature while Chrony is being used.) Storage Temperature
range: 14o Fahrenheit to 120o Fahrenheit (-10o Celsius to 50o Celsius)
non-condensing. (Ambient temperature must be above dew-point temperature
and not fall below dew-point temperature where the Chrony is being stored,
unless the Chrony is sealed in an air-tight container.)
Accuracy: 99.5% or better. Displayed velocity will not
differ from actual velocity by more than 1 part in 200, i.e., ±10
fps on a velocity reading of 2000 fps. Typical performance is generally
better, and shot-to-shot repeatability is always more accurate, i.e.,
Reported Mean Instrumental Velocity may differ by as much as 0.5% from
actual mean instrumental velocity, but Standard Deviation calculated from
data gathered with a Chrony will always be closer than 0.5% to
actual Standard Deviation for a string. This is an important fact because
an accurate measurement of a load’s uniformity is of considerably
more importance than is an exact measure of its average velocity.
LCD Display: 0.5" (1.37 cm) high; Weight: 2.5 lbs
Battery life: 48 hours of continuous use. Photo sensors have wide sensitivity
range, and are electronically calibrated to obtain maximum accuracy.
Should you have to return your Chrony because of a malfunction, do not
return it to the Dealer, Distributor or Mail-Order House you bought it
from. It must be returned directly to SHOOTING CHRONY, INC.
residents, please return your CHRONY to:
SHOOTING CHRONY INC.
3840 East Robinson Rd., PMB # 298
Amherst, NY 14228 USA
residents and other Non-U.S.
senders please return your CHRONY to:
SHOOTING CHRONY INC.
2446 Cawthra Rd, Building 1, Unit 10
CANADA, L5A 3K6
Phone: 1-(905) 276-6292; FAX: 1-(905) 276-6295
||If it doesn't unfold, it's not a Chrony®
|Copyright © 1997-2009
Last updated: July, 2009
Pricing effective: · E. & O. E.