A while back, Cal Zant at PrecisionRifleBlog.com did a big muzzle brake comparison test. Along with measuring recoil reduction, Cal’s team recorded sound levels in PRB’s exhaustive muzzle brake field test. In the PRB archives you’ll find comprehensive muzzle brake sound test results, with hard data on 20 different muzzle brakes.
Sound can be a tricky subject, but Cal Zant, the editor of PrecisionRifleBlog.com, presents everything an informed shooter should know about muzzle brake noise in a straightforward and practical way. Most sound tests are measured from the side of the muzzle, in accordance with mil-spec standards, and Cal did that. But he also measured the sound level of each brake from behind the rifle, closer to the shooter’s position. This provides a more accurate indicator of the actual sound levels firearms operators will encounter while shooting.
Muzzle brakes ARE really loud — that’s something most active shooters have observed. But this study finally gives us some hard data and makes objective comparisons. The difference between brakes was quite significant. Some brakes were ear-splitting — more than twice as loud as other brakes tested.
As a bonus, Cal also provides data on how the new Ultra series suppressors from Thunder Beast Arms Corp (TBAC) compare in terms of sound level behind the rifle.
A couple seasons back, PrecisionRifleBlog.com (PRB) published a significant field test of powder temperature stability. The test was designed to quantify the temperature stability of Hodgdon H4350 and Varget powders compared to IMR’s Enduron line of powders, specifically IMR 4166 and 4451. The results were very interesting, to say the least…
Hodgdon Extreme Series powders have attracted quite a fan base, with over 90% of the top shooters in the Precision Rifle Series choosing to run one of those powders. IMR offers a modern line of powders “with Enduron Technology” — which is also marketed to have “extreme temperature stability”. Sounds familiar! These new powders should compete directly with the Hodgdon Extreme Series, which gives shooters more temp-stable powder options to consider.
The top shooters in the PRS and veteran long-range shooters in other disciplines have learned to value a temperature-stable powder. That’s because a change in temperature can affect the trajectory or “flight path” of the bullet in two well-known ways:
1. Assuming all other environmental conditions remain the same, an increase in air temperature will cause a flatter trajectory due to a lower air density (easier for the bullet to cut through the air).
2. The same increase in temperature also causes the nitrocellulose-based powder inside the cartridge to burn at a higher rate, producing approximately four times the Point of Impact (POI) shift than just air temperature alone. (SEE: Temperature Effects On Zero on KestrelMeters.com.)
“The initial heat condition of your powder will affect the burn rate,” Bryan Litz explained at a recent Applied Ballistics Seminar. That means swings in ambient outside temperature can affect your internal ballistics, which will directly affect your muzzle velocity, which will change your bullet’s trajectory. Some powders are more affected by changes in temperature than others. So if your goal is first-shot hits and you may shoot in a variety of conditions — you should care about temperature stable powders.
The folks at PrecisionRifleBlog.com meticulously loaded 6.5×47 Lapua ammo with each powder using some of the best equipment available. This included the top-of-the-line Prometheus Gen II Powder Scale, which is capable of loading to the nearest kernel of powder. This ensured the powder charges were identical for each round of ammo. PRB’s testers explain the full set of equipment and steps in their loading process in the Full Test Report.
Once they had a couple dozen rounds loaded with each powder, they went and shot them with each powder at 25° F, 65° F, and 140° F. The muzzle velocity of each shot was recorded using BOTH a LabRadar Doppler Radar and a MagnetoSpeed Chronograph. That provided two sets of velocity numbers. When placed and configured optimally, the LabRadar can measure muzzle velocity with +/- 0.1% accuracy, according to the manufacturer.
Here are the results from the PRB Powder Temp Stability Tests:
You can see Hodgdon H4350 had the least variance in muzzle velocity, with just 25 fps over the 115° swing in temperature! That is very, very low. Hodgdon Varget was the second least temperature sensitive powder in this test, with 46 fps of variance in muzzle velocity between temperatures of 25° F and 140° F. IMR 4166 performed very similar to Varget, and proved to be fairly insensitive to large swings in temperature. IMR 4451 had the largest swing in muzzle velocity of the powders tested, but keep in mind just 68 fps over 115° F swing is still a good performance.
Most powders aren’t specially formulated to be temperature stable. So they would likely show much larger swings than what these four top-performing powders showed. However, Alliant’s relatively new Reloder 16 is an extremely temp-stable powder, with a burn rate that is a close match to H4350. Many F-Open competitors are now using Reloder 16 with considerable success.
PRB’s test team also noticed other interesting trends in the data. For example, variation in velocity does NOT appear to be linear across the full range of temperatures. By that, they mean the change per degree from 20° to 65° might be smaller or larger than the change per degree from 65° to 140°.
Well folks, it’s July 1st already — the means we’re moving into “peak heat” summer conditions. It’s vitally important to keep your ammo at “normal” temps during the hot summer months. Even if you use “temp-insensitive” powders, studies suggest that pressures can still rise dramatically when the entire cartridge gets hot, possibly because of primer heating. It’s smart to keep your loaded ammo in an insulated storage unit, possibly with a Blue Ice Cool Pak if you expect it to get quite hot. Don’t leave your ammo in the car or truck — temps can exceed 140° in a vehicle parked in the sun.
To learn more about how ambient temperature (and primer choice) affect pressures (and hence velocities) you should read the article Pressure Factors: How Temperature, Powder, and Primer Affect Pressure by Denton Bramwell. In that article, the author uses a pressure trace instrument to analyze how temperature affects ammo performance. Bramwell’s tests yielded some fascinating results.
For example, barrel temperature was a key factor: “Both barrel temperature and powder temperature are important variables, and they are not the same variable. If you fail to take barrel temperature into account while doing pressure testing, your test results will be very significantly affected. The effect of barrel temperature is around 204 PSI per F° for the Varget load. If you’re not controlling barrel temperature, you about as well might not bother controlling powder temperature, either. In the cases investigated, barrel temperature is a much stronger variable than powder temperature.”
Powder Heat Sensitivity Comparison Test
Cal Zant of the Precision Rifle Blog has published a fascinating temp-stability comparison test of four powders: Hodgdon H4350, Hodgdon Varget, IMR 4451, and IMR 4166. The first two are Hodgdon Extreme powders, while the latter two are part of IMR’s new Enduron line of propellants.
The testers measured the velocity of the powders over a wide temperature range, from 25° F to 140° F. Hodgdon H4350 proved to be the most temp stable of the four powders tested.
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PrecisionRifleBlog.com recently reviewed several video-based rifle training DVD sets. While instructional DVDs will never replace live “hands-on” training, they can be cost-effective ways to sharpen your skills. Watched periodically, these training DVDs can help reinforce the fundamentals.
PRB’s Editor Cal Zant has purchased several rifle training DVDs over the years. His recent Precision Rifle Blog DVD review looks at four different options:
Long Range Made Easy, Two-Volume Set, from Accuracy 1st The Art Of The Precision Rifle, with Todd Hodnett (Magpul Dynamics) Putting Rounds On Target, with Bryan Litz (Applied Ballistics) Rifles Only — Precision Rifle Instructional DVDs, with Jacob Bynum
Cal reports that each of these four titles offers a slightly different approach, with each instructor displaying his own focus, based on his background and expertise.
Accuracy 1st’s Long Range Made Easy Two-Volume Set seemed to win PRB’s Editor’s Choice Award. The tagline on the DVD is: “Go from basic to advanced with the guy that has trained our best military snipers for the past 10 years.” That’s a pretty good description. Todd Hodnett is the primary instructor, and Bryan Litz joins him in several segments.
It’s the best of both worlds. Todd Hodnett’s pragmatic “the-bullet-cannot-lie” approach (field-proven by hundreds of the world’s best snipers), is combined with Bryan Litz’s engineering approach and vast knowledge of external ballistics verified with carefully recorded live-fire experiments. The two styles complement each other well, and provide an extremely well-rounded and comprehensive overview.
The DVD set is split into two volumes, each of which includes two discs. All together there are almost four hours of instruction from the most respected guys in the industry. And they cover a lot of ground — you’d never be able to cover this much in a one- or two-day live class. Plus with the DVD you can easily repeat an important point, and watch the whole program more than once.
Cal paid $76.95 out-of-pocket for the Long Range Made Easy, Vol. 1 & 2 Bundle, so his review wasn’t a paid advertisement. He thought this set provides a ton of value, and could help a lot of shooters. Here are key topics covered in Long Range Made Easy:
■ Advice for Gear Purchases
■ Optimal Gun Setup
■ Technique for Position
■ Simple & Quick Wind Formula
■ Using the Applied Ballistics Kestrel
■ Truing Ballistic Algorithms, Drag Scale Factoring, and Custom Drag Models
■ WEZ Analysis
■ Wind Course
If you’re new to the long range game, or you’ve been doing it for a few years and want to learn directly from some of the most sought-after instructors in the world, then check out Cal’s write-up over at PrecisionRifleBlog.com. CLICK HERE for PRB Review of Training DVDs.
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For a prone shooter, particularly on dusty, dirty or sandy ground, muzzle blast is a major bummer. Muzzle blast can be very disturbing — not just for the trigger-puller but for persons on either side of the gun as well. Some muzzle brakes send a huge shockwave back towards the shooter, and others send blast towards the ground, kicking dirt and debris into the prone shooter’s face. If there was a way to illustrate those factors — shockwave and debris — that might help shooters select one brake design over another.
Cal Zant at PrecisionRifleBlog.com applied a unique blend of creativity and resourcefulness to try to answer that question for 20+ muzzle brakes. Using high-speed photography and household products, he captured the blast pattern of 20+ different brake designs for easy side-by-side comparison. Can you figure out how Cal managed to show muzzle brake blasts so clearly? His “hi-viz” solution, revealed in the article, is very clever. See the eye-opening results for 20+ brakes, with illustrative photos, by visiting the Precision Rifle Blog Muzzle Brake Ground Signature Test Page.
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PrecisionRifleBlog.com (PRB) recently published results from a field test PRB conducted to quantify the temperature stability of the popular Hodgdon H4350 and Varget powders and compare those to IMR’s new Enduron line of powders, specifically IMR 4166 and 4451.
Hodgdon Extreme Series powders have attracted quite a fan base, with over 90% of the top shooters in the Precision Rifle Series choosing to run one of those powders. IMR recently released a new line of powders “with Enduron Technology” — which is also marketed to have “extreme temperature stability”. Sounds familiar! These new powders should compete directly with the Hodgdon Extreme Series, which gives shooters more temp-stable powder options to consider.
The top shooters in the PRS and veteran long-range shooters in other disciplines have learned to value a temperature-stable powder. That’s because a change in temperature can affect the trajectory or “flight path” of the bullet in two well-known ways:
1. Assuming all other environmental conditions remain the same, an increase in air temperature will cause a flatter trajectory due to a lower air density (easier for the bullet to cut through the air).
2. The same increase in temperature also causes the nitrocellulose-based powder inside the cartridge to burn at a higher rate, producing approximately four times the Point of Impact (POI) shift than just air temperature alone. (SEE: Temperature Effects On Zero on KestrelMeters.com.)
“The initial heat condition of your powder will affect the burn rate,” Bryan Litz explained at a recent Applied Ballistics Seminar. That means swings in ambient outside temperature can affect your internal ballistics, which will directly affect your muzzle velocity, which will change your bullet’s trajectory. Some powders are more affected by changes in temperature than others. So if your goal is first-shot hits and you may shoot in a variety of conditions — you should care about temperature stable powders.
The folks at PrecisionRifleBlog.com meticulously loaded 6.5×47 Lapua ammo with each powder using some of the best equipment available. This included the top-of-the-line Prometheus Gen II Powder Scale, which is capable of loading to the nearest kernel of powder. This ensured the powder charges were identical for each round of ammo. PRB’s testers explain the full set of equipment and steps in their loading process in the Full Test Report.
Once they had a couple dozen rounds loaded with each powder, they went and shot them with each powder at 25° F, 65° F, and 140° F. The muzzle velocity of each shot was recorded using both a LabRadar Doppler Radar and a MagnetoSpeed Chronograph. The LabRadar is a new type of device that allows you to measure muzzle velocity within at least +/- 0.1% of the reading.
Here are the results from the PRB Powder Temp Stability Tests:
You can see Hodgdon H4350 had the least variance in muzzle velocity, with just 25 fps over the 115° swing in temperature! That is very, very low. Hodgdon Varget was the second least temperature sensitive powder in this test, with 46 fps of variance in muzzle velocity between temperatures of 25° F and 140° F. IMR 4166 performed very similar to Varget, and proved to be fairly insensitive to large swings in temperature. IMR 4451 had the largest swing in muzzle velocity of the powders tested, but keep in mind just 68 fps over 115° F swing is still a good performance.
Most powders aren’t specially formulated to be temperature stable. So they would likely show much larger swings than what these four top-performing powders showed.
PRB’s test team also noticed other interesting trends in the data. For example, variation in velocity does NOT appear to be linear across the full range of temperatures. By that, they mean the change per degree from 20° to 65° might be smaller or larger than the change per degree from 65° to 140°.
There’s an all-new book from Applied Ballistics. Modern Advancements in Long Range Shooting – Volume II, is now available for pre-order from the Applied Ballistics eStore. This 356-page hardcover resource is chock full of information, much of it derived through sophisticated field testing. The pre-order price is $34.95, $5.00 off the regular $39.95 price. The books are expected to ship in July, 2016.
AUDIO FILE: Bryan Litz Talks about Modern Advancements in Long Range Shooting, Volume 2. (Sound file loads when you click button).
Volume II of Modern Advancements in Long Range Shooting contains all-new content derived from research by Applied Ballistics. Author Bryan Litz along with contributing authors Nick Vitalbo and Cal Zant use the scientific method and careful testing to answer important questions faced by long range shooters. In particular, this volume explores the subject of bullet dispersion including group convergence. Advanced hand-loading subjects are covered such as: bullet pointing and trimming, powder measurement, flash hole deburring, neck tension, and fill ratio. Each topic is explored with extensive live fire testing, and the resulting information helps to guide hand loaders in a deliberate path to success. The current bullet library of measured G1 and G7 ballistic coefficients is included as an appendix. This library currently has data on 533 bullets in common use by long range shooters.
Bryan tells us that one purpose of this book is to dispel myths and correct commonly-held misconceptions: “Modern Advancements in Long Range Shooting aims to end the misinformation which is so prevalent in long range shooting. By applying the scientific method and taking a Myth Buster approach, the state of the art is advanced….”
Bullet Dispersion and Group Convergence
Part 1 of this Volume is focused on the details of rifle bullet dispersion. Chapter 1 builds a discussion of dispersion and precision that every shooter will benefit from in terms of understanding how it impacts their particular shooting application. How many shots should you shoot in a group? What kind of 5-shot 100 yard groups correlate to average or winning precision levels in 1000 yard F-Class shooting?
Chapter 2 presents a very detailed investigation of the mysterious concept of group convergence, which is the common idea that some guns can shoot smaller (MOA) groups at longer ranges. This concept is thoroughly tested with extensive live fire, and the results answer a very important question that has baffled shooters for many generations.
Part 2 of this Volume is focused on various aspects of advanced hand-loading. Modern Advancements (Vol. II) employs live fire testing to answer the important questions that precision hand loaders are asking. What are the best ways to achieve MVs with low ES and SD? Do flash hole deburring, neck tension, primer selection, and fill ratio and powder scales sensitivity make a difference and how much? All of these questions are explored in detail with a clear explanation of test results.
One of the important chapters of Part 2 examines bullet pointing and trimming. Applied Ballistics tested 39 different bullet types from .224 through .338 caliber. Ten samples of each bullet were tested for BC in each of the following configurations: original out of the box, pointed, trimmed, pointed and trimmed. The effect on the average BC as well as the uniformity in BC was measured and tabulated, revealing what works best.
Part 3 covers a variety of general research topics. Contributing author Nick Vitalbo, a laser technology expert, tested 22 different laser rangefinders. Nick’s material on rangefinder performance is a landmark piece of work. Nick shows how shooters can determine the performance of a rangefinder under various lighting conditions, target sizes, and reflectivities.
Chapter 9 is a thorough analysis of rimfire ammunition. Ballistic Performance of Rifle Bullets, 2nd Edition presented live fire data on 95 different types of .22 rimfire ammunition, each tested in five different barrels having various lengths and twist rates. Where that book just presented the data, Chapter 9 of this book offers detailed analysis of all the test results and shows what properties of rimfire ammunition are favorable, and how the BCs, muzzle velocities and consistency of the ammo are affected by the different barrels.
Chapter 10 is a discussion of aerodynamic drag as it relates to ballistic trajectory modeling. You will learn from the ground up: what an aerodynamic drag model is, how it’s measure and used to predict trajectories. Analysis is presented which shows how the best trajectory models compare to actual measured drop in the real world.
Finally, contributing author Cal Zant of the Precision Rifle Blog presents a study of modern carbon fiber-wrapped barrels in Chapter 11. The science and technology of these modern rifle barrels is discussed, and then everything from point of impact shift to group sizes are compared for several samples of each type of barrel including standard steel barrels.
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For a prone shooter, particularly on dusty, dirty or sandy ground, muzzle blast is a major bummer. Muzzle blast can be very disturbing — not just for the trigger-puller but for persons on either side of the gun as well. Some muzzle brakes send a huge shockwave back towards the shooter, and others send blast towards the ground, kicking dirt and debris into the prone shooter’s face. If there was a way to illustrate those factors — shockwave and debris — that might help shooters select one brake design over another.
Cal Zant at PrecisionRifleBlog.com applied a unique blend of creativity and resourcefulness to try to answer that question for 20+ muzzle brakes. Using high-speed photography and household products, he captured the blast pattern of 20+ different brake designs for easy side-by-side comparison. Can you figure out how Cal managed to show muzzle brake blasts so clearly? His “hi-viz” solution, revealed in the article, is very clever. See the eye-opening results for 20+ brakes, with illustrative photos, by visiting the Precision Rifle Blog Muzzle Brake Ground Signature Test Page.
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Sound can be a tricky subject, but Cal Zant, the editor of PrecisionRifleBlog.com, presents everything an informed shooter should know about muzzle brake noise in a straightforward and practical way. Most sound tests are measured from the side of the muzzle, in accordance with mil-spec standards, and Cal did that. But he also measured the sound level of each brake from behind the rifle, closer to the shooter’s position. This provides a more accurate indicator of the actual sound levels firearms operators will encounter while shooting.
Muzzle brakes ARE really loud — that’s something most active shooters have observed. But this study finally gives us some hard data and makes objective comparisons. The difference between brakes was quite significant. Some brakes were ear-splitting — more than twice as loud as other brakes tested.
As a bonus, Cal also provides data on how the new Ultra series suppressors from Thunder Beast Arms Corp (TBAC) compare in terms of sound level behind the rifle.
Another massive, data-driven field test has been completed by our friend, Cal Zant, over at PrecisionRifleBlog.com. The past few months, Cal has tested 20+ muzzle brakes designed for 6mm, 6.5mm, and .30-caliber precision rifles. Hundreds of hours have gone into this research, and it provides a lot of new insight and empirical data for several aspects of muzzle devices. Cal put a huge amount of labor/engineering into these tests and his findings deserve to be widely read.
Recoil Reduction
Cal created a system to directly measure the entire recoil force signature of each muzzle brake using high-speed sensors. Although the recoil cycle happens very quickly (around 1/100th of a second), his test equipment could record up to 1,000 force data points during a single recoil cycle! He fired over 1,000 rounds of match-grade ammo through four different rifles: 6XC, 6.5 Creedmoor, .308 Win, and the monster .300 Norma Magnum. He literally spent thousands of dollars on this part of the test, to ensure he got it right.
Cartridge Types Tested: 6XC, 6.5 Creedmoor, .308 Win, and .300 Norma Magnum
Ability To Stay On Target
David Tubb helped Cal develop this part of the test, because David believes this is the most important aspect of a muzzle brake. Using a laser and high-speed camera, Cal was able to objectively quantify how well each design helped you stay on target.
Noise Level
Muzzle brakes are loud, but some are louder than others … three to four times as loud. Cal enlisted the help of an expert from the suppressor industry to precisely measure how much louder each muzzle brake made a rifle. Each brake was tested in accordance with MIL-STD-1474D using calibrated military-approved equipment, and the noise level was also tested at the shooter’s position. This produced some interesting results.
Zant also includes high-res photos of each brake, and plans to publish other info about each model (including price, whether it requires gunsmithing, what calibers it is available in, etc.) to make it easy to compare them side-by-side.
Cal recently started publishing the results of these tests, and there is already a lot of interesting info. The data might surprise a few people and even dispel a few myths. Particularly interesting is Zant’s comparison of recoil reduction with a suppressor compared to muzzle brakes. How do you think the suppressor performed compared to the brakes? You may be surprised.
MIL or MOA — which angular measuring system is better for target ranging (and hold-offs)? In a recent article on his PrecisionRifleBlog.com website, Cal Zant tackles that question. Analyzing the pros and cons of each, Zant concludes that both systems work well, provided you have compatible click values on your scope. Zant does note that a 1/4 MOA division is “slightly more precise” than 1/10th mil, but that’s really not a big deal: “Technically, 1/4 MOA clicks provide a little finer adjustments than 1/10 MIL. This difference is very slight… it only equates to 0.1″ difference in adjustments at 100 yards or 1″ at 1,000 yards[.]” Zant adds that, in practical terms, both 1/4-MOA clicks and 1/10th-MIL clicks work well in the field: “Most shooters agree that 1/4 MOA or 1/10 MIL are both right around that sweet spot.”
Zant does note that a whopping 94% of shooters in the Precision Rifle Series (PRS) used a mil-based reticle. However, Zant says: “This does NOT mean MIL is better. It just means MIL-based scopes are more popular.” Zant agrees with Bryan Litz’s take on the subject: “You can’t really go wrong with either (MIL or MOA). They’re both equally effective, it comes down to how well you know the system. If you’re comfortable with MOA, I wouldn’t recommend switching to MIL. I have a few MIL scopes but primarily because they’re on rifles used for military evaluation projects, and that community is now mostly converted to MILS, so when in Rome….”
We recommend you read Zant’s complete article which is very thorough and is illustrated with helpful graphics. Here are the key points Zant makes in his MIL vs. MOA analysis:
MIL vs. MOA — Key Points
There are a handful of minor differences/trade-offs between MIL & MOA, but there are no inherent advantage to either system. Most people blow the small differences WAY out of proportion….Here are the biggest differences and things to keep in mind:
Whatever you decide, go with matching turret/reticle (i.e. MIL/MIL or MOA/MOA)
1/4 MOA adjustments are slightly more precise than 1/10 MIL.
MIL values are slightly easier to communicate.
If you think in yards/inches the math for range estimation is easier with MOA. If you think in meters/cm the math is easier with MIL.
When your shooting partners are using one system, there can be some advantage to having the same system.
Around 90% of the PRS competitors use MIL.
There are more product options (with ranging reticles) in MIL.
Range Card Print-Outs
Zant makes an interesting practical point regarding range card print-outs. He suggests the MIL System may be easier to read: “You can see in the range card examples below, 1/4 MOA adjustments take up more room and are a little harder to read than 1/10 MIL adjustments.”
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PrecisionRifleBlog.com recently published results from the most comprehensive field test of rangefinder binoculars ever conducted. It included virtually every product available in a variety of real-world scenarios, to see which had the best performance in the field in terms of both optical clarity and ranging capabilities. The results are based on over 10,000 data points collected from the field over 3 months of testing. Cal Zant, author of PrecisionRifleBlog.com, published a series of posts with exhaustive details about his optical and ranging tests and results, but we’ll hit the highlights here.
VOICE FILE: Click Button to Hear Cal Zant TALK about Rangefinder Binocular Test
Six of the models tested were binoculars, and the other two were monoculars. The Leupold monocular was included for reference, because many shooters have a 1,000-yard rangefinder similar to the RX-1000. The Vectronix Terrapin model was included as the control for ranging performance, because it is known to be an extremely accurate rangefinder (spoiler alert: it is). Cal provides a very detailed side-by-side spec comparison for these models in one of his posts.
Ranging Test Results
Each model was used to range 500+ times in a variety of scenarios from 25 to over 30,000 yards. The tests showed these models had similar performance at close and mid-range targets, but at 600 yards their performance started to diverge … so that is where most of the testing was focused.
The chart below summarizes the ranging performance found on the test targets in ideal conditions, which was from a sturdy tripod, at sunset, with 10+ mile visibility. The exact target shape and surroundings varied, but the targets were all approximately 2 MOA wide, highly reflective, and perpendicular to the rangefinder. Specifics on target dimensions, view from the ranging position, and target surroundings are given in the detailed ranging performance results post.
Vectronix is the leader of the rangefinder world, and that was proved once again in these tests. The new Leica Geovid HD-B wasn’t far behind them, with accurate ranging beyond 1 mile. The Zeiss Victory RF also had surgical precision off a tripod, although it had a reduced range compared to the Vectronix and Leica. The Bushnell Fusion 1 Mile also proved to be able to range targets out to their claimed max range of 1,760 yards.
PrecisionRifleBlog.com also tested the ranging performance of each model in bright lighting conditions, and offhand as well. The data from those tests also contained a few surprises. To determine how accurate each model really was, Cal Zant carefully analyzed the results from each model when aimed at precisely positioned, “known distance” targets. To see how those tests turned out, or learn more details about specific models, GO TO full results.
Optical Test Results
For the optics tests, Cal’s goal was to find an objective, data-driven approach to testing optical performance. What he came up with was placing eye exam charts from 600 to 1,400 yards with different size letters, and then recording what two different people could accurately read with each model. The data for each unit was summed into a single score so they could be ranked relative to how much detail the testers could make out. More specifics are provided regarding how the test was conducted and how scores were calculated in the optical performance results post. Here are the results from Cal’s data-driven approach:
The Leica Geovid HD-B edged out the other models for the top spot, with its completely new, Perger-Porro prism design. The original Leica Geovid HD, and Zeiss Victory RF also showed great optical clarity.
The Rest of the Story
Cal’s full series of posts is very informative. He’s done tons of analysis on the data, and summarizes it in several charts that provide a lot of insight. Cal is also in the process of publishing detailed reviews on each model, including notes he and the other testers compiled for each unit. They used them all — a lot, so they have a unique perspective on what’s good or bad about each. Find out more at the link below:
To learn more about how ambient temperature (and primer choice) affect pressures (and hence velocities) you should read the article 
Part 2 of this Volume is focused on various aspects of advanced hand-loading. Modern Advancements (Vol. II) employs live fire testing to answer the important questions that precision hand loaders are asking. What are the best ways to achieve MVs with low ES and SD? Do flash hole deburring, neck tension, primer selection, and fill ratio and powder scales sensitivity make a difference and how much? All of these questions are explored in detail with a clear explanation of test results.
