Want to improve your understanding of Ballistics, Bullet Design, Bullet Pointing, and other shooting-related tech topics? Well here’s a treasure trove of gun expertise. Applied Ballistics offers dozens of FREE tech articles on its website. Curious about Coriolis? — You’ll find answers. Want to understand the difference between G1 and G7 BC? — There’s an article about that.
“Doc” Beech, technical support specialist at Applied Ballistics says these articles can help shooters working with ballistics programs: “One of the biggest issues I have seen is the misunderstanding… about a bullet’s ballistic coefficient (BC) and what it really means. Several papers on ballistic coefficient are available for shooters to review on the website.”
Credit Shooting Sports USA Editor John Parker for finding this great resource. John writes: “Our friends at Applied Ballistics have a real gold mine of articles on the science of accurate shooting on their website. This is a fantastic source for precision shooting information[.] Topics presented are wide-ranging — from ballistic coefficients to bullet analysis.”
Here are six (6) of our favorite Applied Ballistics articles, available for FREE to read online. There are dozens more, all available on the Applied Ballistics Education Webpage. After Clicking link, select Plus (+) Symbol for “White Papers”, then find the article(s) you want in the list. For each selection, then click “Download” in the right column. This will send a PDF version to your device.
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In this .308 Win test, 70° F ammo shot 96 FPS slower than ammo heated to 130.5° F. And the 130.5° ammunition was 145 fps faster than ammo taken right out of the freezer (at 25.5° F). That’s a huge difference…
Today is the first day of August. That means most parts of the country will soon be encountering peak summer heat. Some ranges in the Western states have already recorded temperatures well over 100 degrees F during matches. When dealing with extreme summer heat, you should make a serious effort to keep your ammo at reasonable temperatures. When possible, keep ammo in a cooler in the shade.
Never leave boxes of ammo out in the hot sun. Even with powders advertised as “temp stable” you can see significant velocity increases when ambient temps reach 90 degrees and above. This article explains how temperature extremes (both hot and cold) can alter bullet velocities. The velocity differences between very cold ammo and very hot ammo can be very large, as this article explains.
EDITOR’s NOTE: The Sierra tester does not reveal the brand of powder tested here. Some powders are much more temp sensitive than others. Accordingly, you cannot extrapolate test results from one propellant to another. Nonetheless, it is interesting to see the actual recorded velocity shift with ammo temperature variations in a .308 Win.
Written by Sierra Chief Ballistician Tommy Todd This story originally appeared in theSierra Bullets Blog
A few weeks ago I was attending the Missouri State F-Class Match. This was a two-day event during the summer and temperatures were hot one day and hotter the next. I shot next to a gentleman who was relatively new to the sport. He was shooting a basically factory rifle and was enjoying himself with the exception that his scores were not as good as he hoped they would be and he was experiencing pressure issues with his ammunition. I noticed that he was having to force the bolt open on a couple of rounds. During a break, I visited with him and offered a couple of suggestions which helped his situation somewhat and he was able to finish the match without major issues.
He was shooting factory ammunition, which is normally loaded to upper levels of allowable pressures. While this ammunition showed no problems during “normal” testing, it was definitely showing issues during a 20-round string of fire in the temperatures we were competing in. My first suggestion was that he keep his ammunition out of the direct sun and shade it as much as possible. My second suggestion was to not close the bolt on a cartridge until he was ready to fire. He had his ammo in the direct sunlight and was chambering a round while waiting on the target to be pulled and scored which can take from a few seconds to almost a minute sometimes.
This time frame allowed the bullet and powder to absorb chamber [heat] and build pressure/velocity above normal conditions. Making my recommended changes lowered the pressures enough for the rifle and cartridge to function normally.
Testing Effects of Ammunition Temperature on Velocity and POI
After thinking about this situation, I decided to perform a test in the Sierra Bullets underground range to see what temperature changes will do to a rifle/cartridge combination. I acquired thirty consecutive .30 caliber 175 grain MatchKing bullets #2275 right off one of our bullet assembly presses and loaded them into .308 Winchester ammunition. I utilized an unnamed powder manufacturer’s product that is appropriate for the .308 Winchester cartridge. This load is not at the maximum for this cartridge, but it gives consistent velocities and accuracy for testing.
I took ten of the cartridges and placed them in a freezer to condition.
I set ten of them on my loading bench, and since it was cool and cloudy the day I performed this test I utilized a floodlight and stand to simulate ammunition being heated in the sun.
I kept track of the temperatures of the three ammunition samples with a non-contact laser thermometer.
The rifle was fired at room temperature (70 degrees) with all three sets of ammunition. I fired this test at 200 yards out of a return-to-battery machine rest. The aiming point was a leveled line drawn on a sheet of paper. I fired one group with the scope aimed at the line and then moved the aiming point across the paper from left to right for the subsequent groups.
NOTE that the velocity increased as the temperature of the ammunition did.
The ammunition from the freezer shot at 2451 fps.
The room temperature ammunition shot at 2500 fps.
The heated ammunition shot at 2596 fps.
The tune window of the particular rifle is fairly wide as is shown by the accuracy of the three pressure/velocity levels and good accuracy was achieved across the board. However, notice the point of impact shift with the third group? There is enough shift at 200 yards to cause a miss if you were shooting a target or animal at longer ranges. While the pressure and velocities changed this load was far enough from maximum that perceived over pressure issues such as flattened primer, ejector marks on the case head, or sticky extraction did not appear. If you load to maximum and then subject your ammunition to this test your results will probably be magnified in comparison.
This test showed that pressures, velocities, and point-of-impact can be affected by temperatures of your ammunition at the time of firing. It’s really not a bad idea to test in the conditions that you plan on utilizing the ammo/firearm in if at all possible. It wouldn’t be a bad idea to also test to see what condition changes do to your particular gun and ammunition combination so that you can make allowances as needed. Any personal testing along these lines should be done with caution as some powder and cartridge combination could become unsafe with relatively small changes in conditions.
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SUMMARY: This article reviews a device that “triggers” the LabRadar chronograph to register bullet speed. Rather than activate by sound or Doppler reading, this $35 JKL Inertial Trigger works from the rifle’s instantaneous recoil pulse when a shot is fired. After some frustration with his LabRadar when shooting at a range with reflective surfaces, our tester is now reporting that 100% of his actual shots are being captured correctly by his LabRadar chrono equipped with the JKL Inertial Trigger. He won’t use his LabRadar without it now. Other users have become instant fans of this inertial LabRadar trigger as well. It is very affordable and it works great. VIEW LARGE PHOTO.
JKL Inertial Trigger for LabRadar Chronograph
Product Review by F Class John
The LabRadar chronograph has been one of the most revolutionary tools in the shooting world because of how it collects velocity data, how it reports (and stores) that data, and, ultimately, the ease with which it can be positioned and operated. However, it’s not a perfect system. A majority of the complaints come from users whose LabRadar’s sometimes fail to record all the shots fired in a string. For the average plinker, this may not be an issue. But for serious shooters trying to do ladder tests or load development requiring all shots to be reported, it can be frustrating when a shot is missed.
Traditionally, LabRadar has recommended trying different settings that compensate for the gap between the unit and muzzle as well as well as having different options for how the unit recognizes a shot fired. While these options work to some degree, they aren’t a guaranteed fix especially when shooting at ranges with concrete baffles or with roofs, walls, and dividers that can alter sound waves. While nobody can precisely explain why shots are lost under certain circumstances, the fact remains it DOES happen. In addition, the default system can sometimes pick up stray shots from nearby rifles.
Not willing to give up on this sophisticated chronograph, many shooters have looked for a foolproof way to prevent such failures from happening. In fact, for this shooter, the frustration was so high that I actually sold my first LabRadar and went back to another chronograph before ultimately buying another LabRadar almost a year later. But I made that repeat purchase only after vowing to finding a way to make the LabRadar work — EVERY time, for EVERY shot.
See How JKL Inertial Trigger Works in this Video
JKL Inertial Trigger — Outstanding Product That Works Great
Enter the JKL Trigger for the LabRadar. This is an easy-to-use, inertial-driven trigger that activates simply from the recoil of your gun. The unit consists of a small rectangular pad attached to a long audio cable. All you do is plug in the audio cable, attach the pad to your gun with the provided hook and loop (Velcro) material. Then (important), you must change the LabRadar trigger settings from “Doppler” to “Trigger”. The unit works great and is easy to set up. In my experience, the unit will activate no matter where you place it on a stock. However the recoil of every gun is slightly different, so you will need to make sure you find a location that doesn’t interfere with your shooting setup.
An unexpected benefit of using the JKL trigger is that it gives you a larger area in which to place your Labradar unit, making it more convenient to setup on benches or range stations. I found this a welcome relief since the LabRadar originally seemed somewhat fussy about where I placed it. Now I can place the LabRadar in more convenient locations — as long as it’s still near my gun and pointed at the target correctly, I get consistent bullet speed data.
Are There Issues with “False Positives”?
If there is any downside to using the JKL Inertial Trigger, it’s that a very hard bump or aggressive working of the action can trigger a false reading. However these are easy to identify in your data, because the speed value is way lower than true fired shot values. Simply remove that low entry or otherwise ignore it in your calculations. To be fair, this “bump activation” really doesn’t happen very often once you get used to using the inertial trigger.
SUMMARY — Outstanding Accessory for LabRadar Users
Bottom line — if you own a LabRadar, then definitely get a JKL Inertial Trigger. Priced at just $35.00 this device is not expensive, yet it’s one of the most effective accessories you can buy for the LabRadar. I’ve recommended these inertial triggers to dozens of shooters. Every one of those guys who did buy a JKL trigger says they can’t imagine using a LabRadar without one. If you love what the LabRadar can do, but have been frustrated with shots not getting recorded 100% of the time, then definitely get yourself a JKL Inertial Trigger. It turns a good system into an amazing system. JKL Industries states that its inertial trigger “will work on anything from a .22 LR to a suppressed system or with standard rifle and brake.”
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If you have been waiting to purchase a chronograph… now is a great time to buy. You can get the affordable MagnetoSpeed Sporter for under $180.00 from Brownells. You can set up this device in a few minutes, and you never have to go downrange to fiddle with a tripod or fuss with wires. The MagnetoSpeed Sporter is simple and effective — a no-hassle solution. Be aware, however, that the placement of the Sporter Chrono ON the barrel can affect barrel harmonics. Therefore you should do your final load testing without the Sporter attached.
See MagnetoSpeed Sporter Chronograph Features Reviewed in Video
We’re impressed by the Sporter chrono, as are other shooters — this unit is very popular. Like the MagnetoSpeed V3, the Sporter faithfully records shots, even in complete darkness. Shot strings are recorded digitally and can be transferred to a smart phone via MagnetoSpeed’s XFR accessory (and Apps).
The Magnetospeed Sporter offers most of the features of the more expensive models (see chart below for details) and has a updated sensor. MagnetoSpeed says the Sporter is “Ideal for contoured rifle barrels (sporter barrels) and long-barreled revolvers.” The Sporter Chronograph Kit (shown above) includes: Bayonet Sensor, 3.5 foot Data Cable, Remote Display (with Battery), Strap with thumb nut, Two V-block spacers, and compact storage box.
Q: Will the Sporter Chrono work with thicker barrel (i.e. greater than 1″ diameter)?
A: The manufacturer recommends the $399.00 V3 model for thicker barrels. But, wink-wink, if you have a 1.25″ barrel you can get this to work, based on what we’ve seen. If you have a really fat barrel (up to 2.0″ diameter), get the V3. Magnetospeed also says the V3 is needed for airguns, shotguns, and muzzleloaders.
Click Image for Full-Screen Photo
The Sporter Chrono attaches quickly and easily. It has a 3.5-foot-long cord, and will work with Muzzle Brakes and Flash-hiders up to 2.7″ long.
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If you have been waiting to purchase a chronograph… now is a great time to buy. You can get the affordable MagnetoSpeed Sporter for under $160.00! You can set up this device in a few minutes, and you never have to go downrange to fiddle with a tripod or fuss with wires. The MagnetoSpeed Sporter is simple and effective — a no-hassle solution.
See MagnetoSpeed Sporter Chronograph Features Reviewed in Video
We’re impressed by the Sporter chrono, as are other shooters — this unit is very popular. Like the MagnetoSpeed V3, the Sporter faithfully records shots, even in complete darkness. Shot strings are recorded digitally and can be transferred to a smart phone via MagnetoSpeed’s XFR accessory (and Apps).
The MagnetoSpeed Sporter chrono is less than half the price of previous MagnetoSpeed models. This is big news for shooters who always wanted a MagnetoSpeed but found the $379.00 cost (for V3 model) too pricey. The Sporter Chronograph costs just $159.99 at MidwayUSA (see below) and $179.00 at Amazon.
The Magnetospeed Sporter offers most of the features of the more expensive models (see chart below for details) and has a updated sensor. MagnetoSpeed says its new Sporter is “Ideal for contoured rifle barrels (sporter barrels) and long-barreled revolvers.” The Sporter Chronograph Kit (shown above) includes: Bayonet Sensor, 3.5 foot Data Cable, Remote Display (with Battery), Strap with thumb nut, Two V-block spacers, and compact storage box.
Q: Will the Sporter Chrono work with thicker barrel (i.e. greater than 1″ diameter)?
A: The manufacturer recommends the $399.00 V3 model for thicker barrels. But, wink-wink, if you have a 1.25″ barrel you can get this to work, based on what we’ve seen.. If you have a really fat barrel (up to 2.0″ diameter), get the V3. Magnetospeed also says the V3 is needed for airguns, shotguns, and muzzleloaders.
Click Image for Full-Screen Photo
The Sporter Chrono attaches quickly and easily. It has a 3.5-foot-long cord, and will work with Muzzle Brakes and Flash-hiders up to 2.7″ long.
This post essentially puts twenty bucks in your pocket if you need a chronograph. You see the MagnetoSpeed Sporter Chrono typically costs around $180.00 from most vendors. But right now MidwayUSA is running a special — the true “shopping cart price” is $159.99. That’s $20.00 cheaper than Midway’s regular $179.99 price, and $19.00 cheaper than the lowest price we found anywhere else. But this special “Shopping Cart Discount” may not last long, so you may want to act quickly. We confirmed Midway’s $159.99 price on the morning of November 7, 2020.
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MagnetoSpeed’s technology has completely changed the market for firearms chronographs. With a MagnetoSpeed barrel-mounted chrono you can quickly and easily record muzzle velocity (MV) without having to set up tripods or walk down-range. The compact MagnetoSpeed chronos are easy to set up and transport. With the full-featured V3 model, everything you need comes in a small fitted case. In the top photo are the components used with the MagnetoSpeed V3 Kit:
1. V3 Bayonet sensor
2. Display and control unit
3. Bayonet spacers (plastic and rubber)
4. Cords and mounting hardware (left), suppressor heat shield (right)
5. Alignment rod (square cross-section)
6. Rail adapter (sold separately)
Our friend Gavin Gear of UltimateReloader.com reviewed the MagnetoSpeed V3 and came away impressed. Gavin explains that a good chrono is essential: “If you want to load and shoot precision ammunition, you need the tools that will produce and validate the precision of your loads. A good chronograph is one of those tools! In this post I’m going to introduce you to the MagnetoSpeed V3 chonograph, the high-end electromagnetic chronograph which fills out the top slot in MagnetoSpeed’s equipment portfolio.”
In this 11-minute video Gavin reviews MagnetoSpeed’s top-of-the-line V3 Chronograph. He shows what ships with the unit, how to set it up for both rifles and pistols, and then he puts it through its paces showing how it captures velocity data. Gavin says he will follow-up with future videos showing how to link the MagnetoSpeed V3 to your mobile phone and how to log velocity data for future reference. To learn more about this high-tech chrono, visit UltimateReloader.com.
SUMMARY: This article reviews a device that “triggers” the LabRadar chronograph to register bullet speed. Rather than activate by sound or Doppler reading, this $35 JKL Inertial Trigger works from the rifle’s instantaneous recoil pulse when a shot is fired. After some frustration with his LabRadar when shooting at a range with reflective surfaces, our tester is now reporting that 100% of his actual shots are being captured correctly by his LabRadar chrono equipped with the JKL Inertial Trigger. He won’t use his LabRadar without it now. Other users have become instant fans of this inertial LabRadar trigger as well. It is very affordable and it works great. VIEW LARGE PHOTO.
JKL Inertial Trigger for LabRadar Chronograph
Product Review by F Class John
The LabRadar chronograph has been one of the most revolutionary tools in the shooting world because of how it collects velocity data, how it reports (and stores) that data, and, ultimately, the ease with which it can be positioned and operated. However, it’s not a perfect system. A majority of the complaints come from users whose LabRadar’s sometimes fail to record all the shots fired in a string. For the average plinker, this may not be an issue. But for serious shooters trying to do ladder tests or load development requiring all shots to be reported, it can be frustrating when a shot is missed.
Traditionally, LabRadar has recommended trying different settings that compensate for the gap between the unit and muzzle as well as well as having different options for how the unit recognizes a shot fired. While these options work to some degree, they aren’t a guaranteed fix especially when shooting at ranges with concrete baffles or with roofs, walls, and dividers that can alter sound waves. While nobody can precisely explain why shots are lost under certain circumstances, the fact remains it DOES happen. In addition, the default system can sometimes pick up stray shots from nearby rifles.
Not willing to give up on this sophisticated chronograph, many shooters have looked for a foolproof way to prevent such failures from happening. In fact, for this shooter, the frustration was so high that I actually sold my first LabRadar and went back to another chronograph before ultimately buying another LabRadar almost a year later. But I made that repeat purchase only after vowing to finding a way to make the LabRadar work — EVERY time, for EVERY shot.
See How JKL Inertial Trigger Works in this Video
JKL Inertial Trigger — Outstanding Product That Works Great
Enter the JKL Trigger for the LabRadar. This is an easy-to-use, inertial-driven trigger that activates simply from the recoil of your gun. The unit consists of a small rectangular pad attached to a long audio cable. All you do is plug in the audio cable, attach the pad to your gun with the provided hook and loop (Velcro) material. Then (important), you must change the LabRadar trigger settings from “Doppler” to “Trigger”. The unit works great and is easy to set up. In my experience, the unit will activate no matter where you place it on a stock. However the recoil of every gun is slightly different, so you will need to make sure you find a location that doesn’t interfere with your shooting setup.
An unexpected benefit of using the JKL trigger is that it gives you a larger area in which to place your Labradar unit, making it more convenient to setup on benches or range stations. I found this a welcome relief since the LabRadar originally seemed somewhat fussy about where I placed it. Now I can place the LabRadar in more convenient locations — as long as it’s still near my gun and pointed at the target correctly, I get consistent bullet speed data.
Are There Issues with “False Positives”?
If there is any downside to using the JKL Inertial Trigger, it’s that a very hard bump or aggressive working of the action can trigger a false reading. However these are easy to identify in your data, because the speed value is way lower than true fired shot values. Simply remove that low entry or otherwise ignore it in your calculations. To be fair, this “bump activation” really doesn’t happen very often once you get used to using the inertial trigger.
SUMMARY — Outstanding Accessory for LabRadar Users
Bottom line — if you own a LabRadar, then definitely get a JKL Inertial Trigger. Priced at just $35.00 this device is not expensive, yet it’s one of the most effective accessories you can buy for the LabRadar. I’ve recommended these inertial triggers to dozens of shooters. Every one of those guys who did buy a JKL trigger says they can’t imagine using a LabRadar without one. If you love what the LabRadar can do, but have been frustrated with shots not getting recorded 100% of the time, then definitely get yourself a JKL Inertial Trigger. It turns a good system into an amazing system. JKL Industries states that its inertial trigger “will work on anything from a .22 LR to a suppressed system or with standard rifle and brake.”
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If you have been waiting to purchase a chronograph… now is a great time to buy. You can get the affordable MagnetoSpeed Sporter for under $158.00. You can set up this device in a few minutes, and you never have to go downrange to fiddle with a tripod or fuss with wires. The MagnetoSpeed Sporter is simple and effective — a no-hassle solution.
See MagnetoSpeed Sporter Chronograph Features Reviewed in Video
We like the Sporter chrono, as do other shooters — this unit is very popular. Like the MagnetoSpeed V3, the Sporter faithfully records shots, even in complete darkness. Shot strings are recorded digitally and can be transferred to a smart phone via MagnetoSpeed’s XFR accessory (and Apps).
The Magnetospeed Sporter offers most of the features of the more expensive models (see chart below for details) and has a updated sensor. MagnetoSpeed says its new Sporter is “Ideal for contoured rifle barrels (sporter barrels) and long-barreled revolvers.” The Sporter Chronograph Kit (shown above) includes: Bayonet Sensor, 3.5 foot Data Cable, Remote Display (with Battery), Strap with thumb nut, Two V-block spacers, and compact storage box.
Q: Will the Sporter Chrono work with thicker barrel (i.e. greater than 1″ diameter)?
A: The manufacturer recommends the $399.00 V3 model for thicker barrels. But, wink-wink, if you have a 1.25″ barrel you can get this to work, based on what we’ve seen.. If you have a really fat barrel (up to 2.0″ diameter), get the V3. Magnetospeed also says the V3 is needed for airguns, shotguns, and muzzleloaders.
Click Image for Full-Screen Photo
The Sporter Chrono attaches quickly and easily. It has a 3.5-foot-long cord, and will work with Muzzle Brakes and Flash-hiders up to 2.7″ long.
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“Shooting Chrony” is a product name. “Shooting Chrony” should not describe (post-mortem) what you have been doing to your chronograph. Sooner or later all of us may make a mistake, and ventilate our chronograph. With luck, the bullet just “wings” your chronograph, and the damage is minor. But if you hit the unit smack dab in the middle, you may have to retire your chrono for good.
A while back, Forum member Jeff M. (aka “JRM850″) experienced a “low blow” that put his Shooting Chrony out of commission. With tongue firmly in cheek, Jeff started a Forum thread entitled Chronograph Not Picking Up Shots in Bright Sunlight Anymore. Looking at the photo at top, the problem is obvious — he ventilated his Chrono.
This was Jeff’s first chrono kill in 23 years of use, so we shouldn’t be too critical. Jeff explained: “I didn’t realize a friend was shifting from a 300-yard target to 100 yards.” The agent of destruction was a low-traveling 58gr V-Max running at 3415 fps. What happened? Well, when one is shooting at 300 yards, the trajectory will be higher than at 100 yards. We should say, however, that this may have been a low shot, or the 100-yard aiming point may have been placed lower to the ground (closer to the bottom of the target frame), as compared to the 300-yard aiming point.
Other Forum members offered some sarcastic responses:
Try it on an overcast day – it might work again.
It looks like the V-Max performed just about as advertised.
Aww…a little duct tape and some Super Glue and you’re good to go.
If you are using a LabRadar or Magnetospeed, your chrono shouldn’t be in the line of fire, but for those will conventional chronos, here’s some good advice…
Double Check Your Aim Point and Trajectory BEFORE You Shoot
The lesson learned here is that you should never change targets (or aim points) without checking your bullet’s flight over the chronograph. We like to align the barrel so the bullet exits a good 6-8 inches above the electronics (check your manual for recommended shot height).
In addition, we always boresight the barrel so we can see the actual target through the bore. Then, with gun UNLOADED, bolt removed and action clear, we look back down the barrel so we can see daylight through the bore, with the gun set on solid rests. If you look through the middle of the “V” formed by the sky screen supports and you can’t see light shining through the barrel’s bore, you probably have a set-up problem and you should re-align the rifle.
Use a Test Backer to Confirm Your Bullet Trajectory
You can put tape on the support rods about 6″ up from the unit. This helps you judge the correct vertical height when setting up your rifle on the bags. Another trick is to hang a sheet of paper from the rear skyscreen and then use a laser boresighter to shine a dot on the paper (with the gun planted steady front and rear). This should give you a good idea (within an inch or so) of the bullet’s actual flight path through the “V” over the light sensors. Of course, when using a laser, never look directly at the laser! Instead shine the laser away from you and see where it appears on the paper.
After you have used the laser boresighter to get the rifle centered up in the chrono’s “sweet spot”, confirm with a test shot or two (see photo). Even when using an in-chamber laser boresighter, it is not uncommon for the bullet’s actual point of impact to be different than the laser’s dot location.
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We see comparison tests of cars, cameras, and other hardware. But how about chronographs? What could we learn by setting up three different chronographs, and running a 20-shot string over all three at the same time. One of our Forum members, Randy S. (aka AAA) did that very test with three of the best chronographs you can buy: LabRadar, MagnetoSpeed, and an Oehler model 35P. The MagnetoSpeed was attached to the barrel of an F-Class rig, with the LabRadar placed on the left side of the shooting bench. The Oehler 35P was positioned about 23 feet downrange. The photo above shows the set-up. A 20-shot string was recorded with the results in a spreadsheet.
AAA talks about this interesting experiment in a Shooters’ Forum Thread. Here is his report:
Comparison Testing Three Chronographs
We all have our favorite chronograph. Each gives a number, but how would that number compare to the same round fired with another chronograph? I wanted to know so a friend and I set up the following test with three chronographs: LabRadar, MagnetoSpeed V3, and Oehler Model 35P.
For the test we fired Berger 105gr VLDs over the three chronographs simultaneously. The test rifle was my 6mm BR Ackley (BRA) F-class rig with fire-formed brass and 200 rounds on the new barrel.
Chronogaphs Tested
LabRadar
MagnetoSpeed V3
Oehler Model 35P
Temperature: 86 deg. F
Elevation: 854 feet
Cartridge: 6mm BRA (105gr Berger VLD)
Time between shots: 45 seconds
To start off, five rounds were fired to make sure all systems were recording and to warm the barrel. Then the test was 20 shots fired across all three instruments with 45 seconds between shots. The Oehler was set 7.5 yards from the muzzle so 12 FPS was added to the recorded value.
We were using the internal trigger on the LabRadar. The manual says the Vo indicated is the actual muzzle velocity when using the internal trigger, but not if using the Doppler. The 12 FPS Oehler adjustment (back to MV) was based on the Berger Ballistics Calculator.
The LabRadar Chronograph is on sale now through 12/7/2019. Buy for $499.95, a $60.00 savings.
Results of the Triple Chronograph Shoot-Out:
LR-M is FPS variance between LabRadar and MagnetoSpeed V3. LR-O is FPS variance between LabRadar and distance-adjusted Oehler 35P. You can see all three chronos were very consistent. ES was identical with the MagnetoSpeed and Oehler 35P, while SD was identical with the LabRadar and Oehler 35P.CLICK HERE for spreadsheet.
The tester, Randy S. (aka AAA) says: “Judge for yourself, but I was impressed by all.”
This is a manufacturer’s photo showing the Magnetospeed V3 as mounted. This is NOT the test set-up.
Comments by Forum Members
Our Forum members expressed interest in this Triple Chronograph test. Some confirmed that the LabRadar and Magnetospeed give very similar FPS numbers, based on their own tests:
“Great test and thanks for sharing. I’ve tested my MagnetoSpeed and LabRadar together and results are always within 2-4 FPS of one another.” — Big D
“Very happy to see your numbers support my decision to buy a MagnetoSpeed. Had read reports comparing it to the Oehler and the numbers I get seem to be supported by my long range shooting results. Many thanks for taking the time and effort [to perform] this comparative test. Always good to get actual test results.” — Texas10
“I did a 4-shot test with my MagnetoSpeed and another shooter’s LabRadar a couple of days ago. The results were within 4 fps with the LabRadar being optimistic.” — Pat Miles
Forum Member Powderbreak studied AAA’s original spreadsheet from the chronograph trio test, then figured out the shot-by-shot FPS variance between the machines. He concluded that all the machines performed very well. Powderbreak posted:
Analyzing the Triple Chronograph Test — What Can We Conclude?
AAA did a great job of comparing the 3 chronos. What conclusions can be drawn?
1) I have not checked the manufacturer’s claims of accuracy, but the three chronos are very close to one another. There is no way for us to determine the actual true velocities, but we do not need to do so. Any of the chronos would be more than adequate for an accurate shooter.
2) The resolution of the three chronographs is actually pretty astounding. One foot per second (FPS) is a resolution of 0.033%.
3) AAA did a great job of reloading a very consistent round. With an extreme spread of 33 fps out of 3014 for 20 rounds, that is only 1.09% total spread of velocities.
4) There is a closer velocity match between the MagnetoSpeed and the LabRadar, but that does not mean the Oehler is less accurate. There is simply an offset between the Oehler and the other two. This could be due to the greater distance, the location, or the internal working of the Oehler.
5) Believe your chronograph, it is probably the most accurate reloading tool that you own.
Brian Litz of Applied Ballistics carefully explained the operation, set-up, accuracy and comparison of AB’s chronographs in his books. [Those books] are well worth the money, and give great insight into the workings of chronographs.” — Powderbreak
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If you have been waiting to purchase a chronograph… now is a great time to buy. You can get the affordable MagnetoSpeed Sporter for under $180.00. You can set up this device in a few minutes, and you never have to go downrange to fiddle with a tripod or fuss with wires. The MagnetoSpeed Sporter is simple and effective — a no-hassle solution.
See MagnetoSpeed Sporter Chronograph Features Reviewed in Video
We’re impressed by the Sporter chrono, as are other shooters — this unit is very popular. Like the MagnetoSpeed V3, the Sporter faithfully records shots, even in complete darkness. Shot strings are recorded digitally and can be transferred to a smart phone via MagnetoSpeed’s XFR accessory (and Apps).
The MagnetoSpeed Sporter chrono is less than half the price of previous MagnetoSpeed models. This is big news for shooters who always wanted a MagnetoSpeed but found the $379.00 cost (for V3 model) too pricey. The new Sporter Chronograph costs just $179.00 at Brownells and $179.00 at Amazon.
The Magnetospeed Sporter offers most of the features of the more expensive models (see chart below for details) and has a updated sensor. MagnetoSpeed says its new Sporter is “Ideal for contoured rifle barrels (sporter barrels) and long-barreled revolvers.” The Sporter Chronograph Kit (shown above) includes: Bayonet Sensor, 3.5 foot Data Cable, Remote Display (with Battery), Strap with thumb nut, Two V-block spacers, and compact storage box.
Q: Will the Sporter Chrono work with thicker barrel (i.e. greater than 1″ diameter)?
A: The manufacturer recommends the $399.00 V3 model for thicker barrels. But, wink-wink, if you have a 1.25″ barrel you can get this to work, based on what we’ve seen.. If you have a really fat barrel (up to 2.0″ diameter), get the V3. Magnetospeed also says the V3 is needed for airguns, shotguns, and muzzleloaders.
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The Sporter Chrono attaches quickly and easily. It has a 3.5-foot-long cord, and will work with Muzzle Brakes and Flash-hiders up to 2.7″ long.
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Put the same load in a variety of barrels (with the same length and chamberings) and you’ll see a wide variance in muzzle velocity. In fact, it’s not unusual to see up to 100 fps difference from one barrel to the next. We demonstrated this with a comparison test of Lapua factory ammo.
Chron Testing Lapua Factory Ammo
At our Southern California test range some years ago, we chronographed Lapua 105gr 6mmBR factory ammo in three different 8-twist barrels of similar length. The results were fascinating. Lapua specs this ammo at 2790 fps, based on Lapua’s testing with its own 26″ test barrel. We observed a speed variance of 67 fps based on tests with three aftermarket barrels.
Barrel Velocity Variance
Brand ‘S’ and Brand ‘PN’ were pre-fit barrels shot on Savage actions. Brand ‘K’ was fitted to a custom action. All test barrels were throated for the 100-108 grain bullets, though there may have been some slight variances in barrel freebore. With a COAL of 2.330″, the rounds were “jumping” to the rifling in all barrels.
Among the four barrels, Brand ‘PN’ was the fastest at 2824 fps average — 67 fps faster than the slowest barrel. Roughly 10 fps can be attributed to the slightly longer length (27″ vs. 26″), but otherwise this particular barrel was simply faster than the rest. (Click Here for results of 6mmBR Barrel Length Velocity Test).
IMPORTANT: Results Are Barrel-Specific, Not Brand-Specific
These tests demonstrate that the exact same load can perform very differently in different barrels. We aren’t publishing the barrel-makers’ names, because it would be wrong to assume that ‘Brand X’ is always going to be faster than ‘Brand Y’ based on test results from a single barrel. In fact, velocities can vary up to 100 fps with two identical-spec barrels from the SAME manufacturer. That’s right, you can have two 8-twist, 26″ barrels, with the same land-groove configuration and contour, from the same manufacturer, and one can be much faster than another.
Don’t Demand More Than Your Barrel Can Deliver
We often hear guys lament, “I don’t get it… how can you guys get 2900 fps with your 6BRs and I can only get 2840?” The answer may simply be that the barrel is slower than average. If you have a slow barrel, you can try using more powder, but there is a good chance it may never run as fast as an inherently fast barrel. You shouldn’t knock yourself out (and over-stress your brass) trying to duplicate the velocities someone else may be getting. You need to work within the limits of your barrel.
Factory Ammo Provides a Benchmark
If you have a .223 Rem, 6mmBR, .243 Win, 6.5×47 Lapua, 6.5 Creedmoor, 6.5×55, .308 Win, 30-06, or .338 LM Rifle, we recommend you buy a box of Lapua factory-loaded ammo. This stuff will shoot great (typically around half-MOA), and it can give you a baseline to determine how your barrel stacks up speedwise. [Editor’s NOTE: The original test was conducted in 2008. The velocity of current-production Lapua factory ammo might be higher or lower, so your results may vary.]
When you complete a new 6mmBR rifle, it’s definitely smart to get a box of the factory ammo and chronograph it. That will immediately give you a good idea whether you have a slow, average, or fast barrel. Then you can set your velocity goals accordingly. For example, if the factory 6BR ammo runs about 2780-2790 fps in your gun, it has an average barrel. If it runs 2820+ in a 26″ barrel (or 2835 fps in a 28″), you’ve got a fast tube.
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Today is the first day of August. That means most parts of the country will soon be encountering peak summer heat. Some ranges in the Western states have already recorded temperatures well over 100 degrees F during matches. When dealing with extreme summer heat, you should make a serious effort to keep your ammo at reasonable temperatures. When possible, keep ammo in a cooler in the shade.
Barrel Velocity Variance
