Estimated reading time: 13 minutes
What Is a Chrono or Chronograph?
In the gun world, a chrono is simply a tool that measures the speed of your bullet.
Table of contents
Who Needs a Chrono?
In my opinion, all shooters! Ballistic solver apps are cheap and easy to get these days and with an app and chrono, anyone can figure out the dope on their rifle. Dope tells you how much the bullet will drop at a given distance. You need accurate data to get good results from the app. A key part of that data is the bullet velocity.
Most manufacturers will print that velocity on the box with rifle ammo or have it available on their website. Most pistol ammo manufacturers also post the velocity of a given round. Many people don’t know those velocities are done with test barrel fixtures. The speeds will often be significantly different than the speeds of your gun. Chronos get an accurate velocity for your gun.
Anyone who wants to shoot a rifle accurately past 150 yards needs a chrono to get accurate dope. This includes hunters, competition shooters, or anyone wanting to make long shots.
Many Purposes
For the casual pistol shooter it’s probably not necessary but it is still useful. Competition pistol shooters need one. In sports like USPSA, IPSC, and IDPA there are Power Factors which are bullet velocity times bullet weight divided by 1000. Power Factors can affect your score (a few points on some hits) if your bullet is too slow. Also, you don’t want it to be way faster than needed, as that adds recoil, affecting your score.
Reloaders can benefit from a chrono when developing loads for rifles and pistols. Most chronos give consistent data like Standard Deviation (SD) and Extreme Spread (ES). The lower these numbers are the more consistent your ammo is. Reloading generally starts with a published load from a manual. A chrono lets you know how the difference between your guns speed and the published load.
In short, not everyone needs a chrono but all shooters can benefit from having one.
Which Chrono?
There are a ton of chronos on the market these days and I decided to compare a few of the top models.
The Labradar
the MagnetoSpeed V3
Older version of the Pact Mark IV timer/chrono combo.
The Garmin and Labradar both use a form of radar to measure velocity. This is often considered the most accurate method. The Magnetospeed measures changes in the magnetic field as a bullet passes over the bayonet. The Pact is old school, two light sensors see the bullet and calculate the speed using time over distance.
They all have pros and cons which I will break down for you.
PACT Mk IV
I’ve had the Pact for about 20 years. There are newer versions that I suspect are better. Back then it was state of the art; it is a shooting timer with super high functionality and also a chrono. It comes with a 24-inch-long metal rail that the sensors are mounted to. Each sensor has a cable that plugs into the back of the unit. Put the rail on a tripod or other flat surface and start shooting.
Pros:
- Accurate and high-tech in its day
- Also a shooting timer
- Works well with suppressors
- No interference from other chronos on the line
- Can be used with more than 2 sensors for more accurate readings
- Displays a ton of data beyond SD and ES
- Durable
- Recorded 10/10 suppressed shots
Cons:
- Need a tripod or other way to mount/hold the sensors
- Less accurate with changing weather
- Can be affected by clouds
- Bulky sensor rail
- Must shoot carefully to not hit the sensors
- The 20+ year-old Pact read significantly slower than the other chronos. There is a good chance it is out of calibration and needs to be returned for recalibration or updates.
Magnetospeed V3
The Magnetospeed is attached to your barrel via a strap. There is an adapter to mount it to Picatinny rails as well. It can be mounted/strapped to a suppressor. The unit has a bayonet that sticks out beyond the muzzle and you use spacers to set it about 3/8” below the barrel exit. The bayonet is attached via cable to the display unit.
Pros:
- Accurate with Suppressors
- General Accuracy
- Has an SD card to save multiple sessions and the data can be downloaded
- Medium size, all items come and fit in a pistol-sized hard case
- No interference from other chronos on the line
- Durable
- Recorded 10/10 suppressed shots
Cons:
- Only displays ES or SD. Must go into the menus to switch between them
- When attached to the barrel it will affect harmonics and accuracy
- Depending on the barrel, muzzle device, and handguard configurations it can be very hard to attach and get accurate readings
- Lots of trial and error when fitting spacers to get the correct distance below the muzzle
- Switching between the strap and the Picatinny system takes a few minutes and is kind of a pain
Labradar
The Labradar has been very popular among shooters for a few years since it was released. It uses radar to “see” the bullet in flight.
Pros:
- Highly accurate
- Lots of data
- Can give velocity for multiple distances that are set by the user
- Stores downloadable data on an SD card
- Can be used with a phone app
Cons:
- The screen uses a small font and can be hard to read (for dudes over 40)
- Must be carefully aimed at the target
- Hard to aim without aftermarket “sight”
- Requires a tripod or other mount for use
- Big and Bulky
- Steep learning curve
- Very finicky with a suppressor and requires an external mic for use
- Semi fragile, I keep mine in a large padded hard case to avoid damage
- Internal AA batteries don’t last long. External battery bank needed for most users
- When other Labradars are on the line each user must manually set the chrono to a different channel
- Recorded 5/10 suppressed shots with the air gun mic attached
Garmin
The Garmin chrono is the newest in my stable. I have used the others for years but only a couple of months for the Garmin. Like the Labradar it uses radar to track the bullet. It comes with a small 4 inch tripod that you can put next to your rifle on the ground or bench. The aftermarket also has mounts to attach it to your rifle or scope via Arca or Picatinny rail.
Pros:
- Tiny and light
- Highly accurate – displays velocity to one decimal
- 6-hour battery life
- Only needs to be aimed in the general direction of the target
- Accurate with suppressors
- Bright easy to read display
- Other Garmin chronos on the line do not interfere
- Works with BB guns, Airsoft, arrows, and almost anything that fires a projectile
- Can be used with the Garmin app
- Recorded 10/10 suppressed shots
- Lots of aftermarket support
Cons:
- Battery not officially user replaceable
- Not officially rated for use mounted to a rifle.
Garmin’s official position on this. “While Garmin did not specifically design or test the use of this product to be mounted to a rifle, aftermarket manufacturers have tested the device mounted to a variety of rifle calibers and the Xero® C1 Pro chronograph has worked without issue. Garmin does not warranty the product when used in a manner outside of the design content.”
Head to Head Chrono Accuracy Comparison
10 shots were fired through all four chronos simultaneously.
| MPA 6.5 CM bolt gun 25 in barrel | 147gr Hornady ELD-M / H4350 Powder | |||||||
| Chrono | Average Velocity | SD | ES | High | Low | Suppressed shots registered | ||
| MagnetoSpeed | 2795.0 | 7.3 | 23 | 2750 | 2727 | N/A | ||
| Labradar | 2741.0 | 7.3 | 24 | 2754 | 2731 | N/A | ||
| Pact | 2670.1 | 4.7 | 10.7 | 2675.5 | 2664.8 | N/A | ||
| Garmin | 2736.0 | 7.9 | 25.9 | 2749.6 | 2723.7 | N/A | ||
| Jakl 5.56mm 13.7 in barrel | 55gr Hornady Steel Match | |||||||
| Magnetospeed | 2797.0 | 16.1 | 43.6 | 2818 | 2769 | 10/10 | ||
| Labradar | 2773.0 | 10.7 | 26 | 2788 | 2762 | 5/10 | ||
| Pact | 2719.7 | 12.5 | 43.6 | 2818 | 2769 | 10/10 | ||
| Garmin | 2791.9 | 16.2 | 53.2 | 2815.9 | 2762.7 | 10/10 | ||
Conclusions:
All the chronos have good and bad points, but for me, the Garmin stands out and is now my go-to choice to take to the range. Ease of use, easy-to-read display, small size and weight, and reliability with suppressors are what make the difference.
READ MORE: Streamlight TLR-6 HL: Little Light, Big Impact
Not everyone needs one of these expensive premium chronos but I do recommend that every shooter has some kind of chrono, or at least have a friend with a chrono. If you are on a budget there are models available for $100-150.
Every shooter can benefit from chrono data.
Garmin Xero Bonus Section!
This story was finished and ready to publish a few weeks ago, then last week I had an idea. Garmin also makes a Launch Monitor for golfers. It measures all kinds of cool stuff like ball speed, club head speed swing path and more. I though it might use similar technology to track projectiles (balls or bullets).
I brought my Xero chrono to the driving range and had a buddy bring his launch monitor. The chrono will pick up projectiles down to 100 FPS, which just under 70 MPH. I set the chrono to look for 100-400 FPS projectiles and grabbed my driver. As I expected it worked! It was showing me the results of ball speed in FPS, about 210 average. Playing in the menus I found that you can display shots in MPH as well.
Hitting a variety of clubs with both the chrono and launch monitor running they gave consistent speeds, usually within 1 MPH of each other. For the average golfer it should pick up your 8 or 9 iron on the low end up to the fastest driver of professional players. Some shooters hate golf, but I know a lot of people that enjoy both and this versatility of the Xero chrono is impressive.
Product Links
Pact Mk IV XP timer and chrono
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You don’t mention the Oehler 35 P. This has been my go-to chronograph for decades. What are your thoughts?
I had an Oehler, Comp Electronics, CED and other chronos but I could not find them to use in this article. The Oehler was super accurate and awesome, but suffers many of the same problems of the PACT and any sky screen chrono. Bulky, takes a while to set up and aim, etc. I would still go with the Garmin due to size, ease of use and accuracy.
Hahaha…what did the other golf players think of the chrono? Some people may not want to know the truth!
I also like the Garmin, however I bought it mainly for shotguns and it does not pick up a shot string anywhere it is placed.. I will record maybe one in 10 shots. All gauges included. Having said that it has never failed to pick up a pistol or rifle bullet. Graet product but louzy for shotguns.
About the Garmin: Wish they had come out with it sooner. Wife bought me a Labradar before the Garmin was available. That’s going to be awkward to swap for a Garmin, because – you know. About the Labradar: What a colossal pain in the butt to use, operate, transport, set up in high wind, accessorize, figure out if it is actually going to track the next shot or not. I am SO disappointed with the Labradar. After two years, I still can’t be sure from shot to shot if the damned thing is going to record ANYTHING at all. Did I mention that the thing EATS batteries faster than a 1965 Sony tape recorder? I am SO SORRY that my wife spent $600 bucks for this finicky piece of junk and that I needed to spend ANOTHER $200 bucks for batteries, then external battery packs, then a Pelican case to prevent it from dying of a bruise, then a tripod, then an external trigger (also junk), then an add-on sight to HOPE the thing is going to track the bullets going to MY target. I wouldn’t wish this Labradar crap on my most irritation stranger at the range. Seriously. If it hadn’t been a gift from my wife, it would already be in a dumpster someplace.