MKIII Championship Timer/Chronograph

1. Introduction

The PACT MKIII Championship Timer was designed to help shooters make effective use of available time by providing accurate time accounting of shots fired and, when desired, audible "cues" to encourage performance while shooting.

The MKIII was built to be user-friendly with minimal button pushing required during operation.

2. Getting Started

Power On/Off

• The on/off switch is located on the back of the MKIII
• When turned on, the timer will:
  • Give a short "BEEP"
  • Display the software version number (e.g., "PACT MKIII w/CHRONO V147.e")
  • Show a copyright notice
  • Display "TIMER COMMAND" with a flashing cursor

Basic Timer Operation

1. Press the GO button
2. After 2-3.5 seconds, you'll hear a beep (your start signal)
3. As you fire, the timer will automatically display and record:
   • Shot number
   • Split time
   • Total time for each shot fired
   • Time between shots
   • Lap times
   • Cues

Display Information

After recording shots, the display will show information such as:

• Example: "#012 .37 6.87" indicates:
  • Shot number 12 was the last shot heard
  • It came .37 seconds after shot 11
  • Total time from start to shot 12 was 6.87 seconds

3. Timer Mode Functions

Reviewing Shots

1. Press the RVW key to see when your first shot occurred
2. Each press of RVW steps to the next shot
3. If you have the optional printer, press PRT to print the string

Finding Specific Shots

1. While reviewing shots, the second line of the display will show "FIND SHOT:"
2. To view a specific shot (e.g., shot 7), press 7 followed by RVW
3. The display will show information for that shot
   • Example: "#007 1.86 3.52" shows shot 7 occurred 1.86 seconds after shot 6

Setting a PAR Time

1. Press the PAR button
2. The display will read "ENTER PAR TIME AND PRESS SET"
3. Enter your desired time limit (e.g., 2.5 seconds by pressing 2, ., 5)
4. Press SET
5. The timer will confirm by displaying the PAR time below "TIMER COMMAND"
6. To remove the PAR time, press PAR then SET without entering a number

PAR Time Results

• If you beat the PAR time, the display will show how much time you had left
  • Example: "PAR .36 2.50" means you had .36 seconds remaining
• If you went over time, the display will show how much you exceeded the limit
  • Example: "#02 .24 2.74" indicates your second shot was .24 seconds after the buzzer

4. Timer Options

Access timer options by pressing the SET/MENU key. These options allow you to simulate complex courses of fire.

Delayed or Random Go

1. At "TIMER COMMAND", press SET
2. The screen will display "DELAYED GO?"
3. Press YES or NO:
   • NO: Timer starts immediately when GO is pressed
   • YES: You'll be asked "RANDOM GO?"
     • NO: Enter a fixed delay time (up to 999.99 seconds)
     • YES: Enter upper and lower delay limits

Benchmarks

After setting up your go command:

1. At "BENCHMARKS?", press YES to set benchmark beeps
2. Enter the time for each beep (e.g., 1, SET, 2, SET, 3, SET, 4, SET)
3. Press SET when finished to return to the main prompt
4. When you press GO, the MKIII will beep at each benchmark time

Keyed Beeps

1. At "KEYED BEEPS?", press YES
2. Enter a shot number followed by SET
3. Enter the delay time after that shot followed by SET
4. Multiple keyed beeps can be set
5. Press SET without entering a number when finished

Stop Plate Options

If using stop plates, you can set "OPEN CIRCUIT STOP PLATES?" to YES (default) or NO depending on your setup.

GO & CST GO Keys

• GO: Clears memory and starts the timer
• CST GO (Comstock Go): Starts the clock at the time of your last shot without clearing memory
  • For Comstock drills, use GO for the first stage and CST GO for subsequent stages
  • Not recommended for match use as accidentally pressing CST GO will cost the shooter their string

Editing Times

When setting Keyed or Benchmark Beeps:

• Previously set times can be edited without retyping all entries
• Press SET for each displayed benchmark to keep it
• Enter a new time to change a benchmark
• Enter zero to delete a benchmark
• For keyed beeps, enter a shot number of zero to delete

LAP Key Function

• The MKIII can function as a stopwatch using the LAP key
• Lap times are recorded similar to shots
• Example: "LAP 2.75 8.63" indicates a lap time 2.75 seconds after the last recorded event, occurring 8.63 seconds after the go command
• Using the LAP key doesn't interfere with timer operation

External Connections

On the back of the MKIII are three 1/8" jacks:

• PLT1 and PLT2: Stop plate inputs
  • Plugging into PLT2 automatically switches to "MVM COMMAND" (Man Vs Man) mode
  • In MVM mode, the microphone is disconnected for dedicated "shoot off" timer functionality
• AUX: Provides 5 volts whenever the buzzer is active
  • Can be used to switch a 5-volt relay (available from electronics stores)
  • Applications include triggering car horns or turning on target movers

Microphone Sensitivity

• If the timer picks up echoes (common on indoor ranges), try placing tape over the microphone
• The sensitivity control is located on the back panel between "PLT 1" and "AUX"
• Turning sensitivity clockwise increases sensitivity
• Factory setting is just sensitive enough to hear a loud hand clap directly over the microphone

5. Chronograph Mode

Setting Up Chronograph Mode

1. From "TIMER COMMAND" press SET, YES
2. The timer will switch to "CHRONO COMMAND" and display the current screen separation
3. Default screen separation is 24 inches
4. To change screen separation, press SET, enter the separation in inches, then press SET again

Recording and Reviewing Shots

1. Press GO to display "Chronograph mode running"
2. Fire a round over your skyscreens
3. The display will show:
   • Shot number and velocity on the top line
   • Current average velocity on the bottom line
   • Example: "#001 856.2 FPS" and "AV 856.2 FPS"
4. For error readings (e.g., "6952.3 FPS"), press the NO key to remove from memory

Statistical Summary

After completing your string, review the data:

1. Press RVW to see high and low velocities with their shot numbers
   • Example: "HI #003 868.2" and "LO #007 823.5"
2. Press RVW again to see Standard Deviation (SD) and Coefficient of Variation (CV)
   • Example: "SD: 45.8" and "CV: 5.99%"
3. Press RVW again to see Mean Absolute Deviation (MAD) and its CV
   • Example: "MAD: 38.4" and "CV: 5.02%"
   • This number is key for comparing load consistency
4. Press RVW again to see Extreme Spread (ES) and Average Velocity
   • Example: "ES: 105.9 FPS" and "AVRG: 763.8 FPS"
5. Continue pressing RVW to review individual shots

Automatic Power Factoring

1. With "CHRONO COMMAND" displayed, press the PAR button
2. At "ENTER BULLET WEIGHT AND PUSH SET", enter the weight (e.g., 200)
3. Press SET
4. Press GO and chronograph a round
5. The display will show the power factor for individual shots

6. SkyScreen System

About the SkyScreens

The MKIII Championship Timer comes with PACT MKV Professional Skyscreens featuring:

• Two lenses that magnify the bullet for more accurate triggering
• Diffuser screens that serve as aiming guides and light diffusers

Setting Up SkyScreens

1. Position skyscreens exactly 24 inches apart (center to center)
   • Any error in screen separation will result in the same percentage error in velocity readings
2. Attach diffuser material to the underside of each arched cross piece
   • Ensure material is smooth without waves
3. Fit side pieces into the cross piece and insert into the skyscreen
4. Connect cables:
   • First screen into the "START" plug on the back of the timer
   • Second screen into the "STOP" plug

Shooting Over SkyScreens

1. Aim so the bullet passes over the center of each screen
2. Maintain 4-6 inches altitude above the screens
3. Set up a clear aiming point to avoid accidentally shooting your second screen

7. Light Conditions and Troubleshooting

General Recommendations

• Give yourself a velocity cushion (25-50 FPS) over required thresholds
• Weather conditions can affect ammo performance

Screen Separation Considerations

• Screen separation can be set from 6 to 120 inches
• Recommended separation: 24 inches for most applications
• For very high velocities (3000+ FPS), consider 36-48 inch separation
• Closer separation is more convenient but slightly less accurate

Light Condition Issues

The MKIII detects decreases in light level when the bullet passes over the screen. Problems may occur when:

1. Blue Sky/Sunlight Issues:

• Sunlight reflecting off bullet can make it brighter than the background
• Solutions:
  • Shoot lower over skyscreens
  • Create shade to the side of screens
  • Change firing direction
  • Tilt skyscreens

2. Indoor/Fluorescent Light Issues:

• Chronographs don't work well with fluorescent lighting
• For indoor use, rig incandescent lights over each screen

8. Muzzle Blast Considerations

Subsonic Ammunition Issues

• With subsonic rounds (below ~1200 FPS), sound reaches skyscreens before the bullet
• If screens shake enough to trigger, you'll get incorrect readings
• Solution: Move further back from the screens

Supersonic Ammunition Precautions

• Keep muzzle a couple feet back from first skyscreen
• Remember: The farther your screens are from muzzle, the lower the velocity reading
• Excessive blast may cause screens to trigger together, producing erroneous readings

Muzzle Blast Shadow Problems

• Occurs when sun is quartering behind you and low on horizon
• Solutions:
  • Change direction of fire
  • Attach small cardboard to front of each skyscreen to shade the slit

Severe Blast Troubleshooting

If the unit appears to "die" when using high-blast firearms:

1. Try firing with a .22 rimfire to verify if blast is the issue
2. Ensure cables touch the ground between MKIII and skyscreens
3. Don't run cables directly under muzzle
4. Place the MKIII behind something solid to block line of sight to muzzle