August 5th, 2019

Applied Ballistics Mobile Lab Maiden Voyage to Texas

Applied Ballistics Texas Mobile Lab Trailer doppler radar Barrett ELR

The folks at Applied Ballistics have a new toy — a large trailer filled with all the latest and greatest tech gear for testing long-range ballistics. Bryan Litz reported: “The maiden voyage for the AB Mobile Lab in Texas this week was a huge success! We look forward to supporting more long range shooting events.” Mitchell Fitzpatrick was there in the Lone Star state with fellow Applied Ballistics staffer Christopher Palka. The Applied Ballistics team will be trailering the Mobile Lab to Indiana where it will be on hand for the NRA National Championships at Camp Atterbury this month.

Applied Ballistics Texas Mobile Lab Trailer doppler radar Barrett ELR
Ten rifles, heaps of cables, huge Doppler Radar unit, military-grade Laser RFs on tripods, spare barrels, safety gear — all ready for action in Texas.

About the Applied Ballistics Mobile Lab

Q: What is the basic purpose of the Applied Ballistics Mobile Lab?

Mitchell Fitzpatrick: The Mobile Lab allows us to effectively carry out ballistics testing in the field and at events. It has most of the capabilities of our normal lab, but on wheels.

Q: What hardware and electronics are carried in the Mobile Lab? What are its capabilities?

Bryan Litz: The Mobile Lab will transport most everything that’s in the main lab including the Doppler radar. This rig is new and we haven’t fully outfitted it yet. The load-outs will be somewhat flexible depending on the venue we are supporting.

Applied Ballistics Texas Mobile Lab Trailer doppler radar Barrett ELR
The three rifles on the left are Barrett MRADS, $6000-$6154 MSRP, before optics.

Applied Ballistics Texas Mobile Lab Trailer doppler radar Barrett ELR

Applied Ballistics Texas Mobile Lab Trailer doppler radar Barrett ELR

NOTE to Readers — Check back at the end of the day. We will have more technical information from Bryan Litz and the Applied Ballistics team…

Permalink Bullets, Brass, Ammo, Tech Tip 1 Comment »
July 28th, 2019

Jumbo $275.00 Magazine for .375 EnABELR Cartridge

.375 cheytac .408 cheytac EnABLER Applied Ballistics Bryan Litz Cadex defense

.375 cheytac .408 cheytac EnABLER Applied Ballistics Bryan Litz Cadex defenseThe .375 EnABELR cartridge was developed to offer magazine feeding capabilities with the highest-BC solid bullets available. Applied Ballistics observes: “The best magazine is one that retains the cartridge shoulder and doesn’t allow the tip of the bullet to impact the front of the magazine during recoil.” Cadex Defense has designed magazines that fit Cadex’s bottom metal and chassis for the EnABELR line of cartridges which allows for maximum magazine fed performance. These mags are beautifully made, but they will be very EXPENSIVE. Expect to pay about $275 per magazine — what the Cadex 375/408 CheyTac magazine currently costs (Product Code: MAG4300, USD $273.95).

Q: Is this different than Cadex’s regular CheyTac magazine?

A: Mitchell Fitzpatrick of Applied Ballistics Weapons Division replied: “Yes, the ribs that retain the shoulder are moved back to hold the case back and prevent the bullet tip from hitting the front of the magazine. We had been playing with inserts welded into place, which worked great, but dedicated mags directly from Cadex was the ultimate goal.”

.375 cheytac .408 cheytac EnABLER Applied Ballistics Bryan Litz Cadex defense
Here is Mitchell Fitzpatrick, shooting the 375 EnABELR in an ELR Competition.

“CADEX and Applied Ballistics. Two companies taking ELR seriously and trying to get that last 1-2% of performance out of the system. Keep up the good work!” — Mark N.

The .375 EnABELR Cartridge — Big and Fast

The .375 EnABELR cartridge is slightly shorter than a .375 CheyTac so it allows the round to mag-feed. Applied Ballistics is currently using brass made by Peterson. The .375 EnABELR has achieved impressive velocities — 2990 FPS — with prototype Berger 379-grain solid bullets fired from a 1:7″-twist 30″ barrel. Applied Ballistics may also test 1:8″-twist and 1:9″-twist barrels. READ Bullet Testing Report.

Berger 379 grain 379gr solid bullet .375 caliber enabler

The .375 EnABELR cartridge was designed to offer .375 CheyTac performance in a slightly shorter package: “The problem with the .375 CheyTac is that, when loaded with the highest performance .375 caliber bullets (379-407 gr Berger Solids, and the 400-425 grain Cutting Edge Lazers) the round is not magazine feed-able in any action that’s sized for CheyTac cartridges.

Berger 379 grain 379gr solid bullet .375 caliber enabler

“Knowing the .375 CheyTac produced substantial performance, and that it was just too long for magazine feeding, made it easy to converge on a design for the .375 EnABELR. We just had to make the case short enough to achieve magazine length with the desired bullets, while adding a little more diameter to keep the case capacity similar to the .375 CheyTac. The resulting basic shape is quite similar in proportions to the successful .338 Norma Magnum Cartridge which, interestingly, was selected as the cartridge for General Dynamics Lightweight Medium Machine Gun (LWMMG).”

Permalink Bullets, Brass, Ammo, Competition, New Product No Comments »
July 11th, 2019

Get Smart — Read FREE Applied Ballistics TECH Articles

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 three dozen 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.”

READ All Applied Ballistics Articles HERE »

Here are six (6) of our favorite Applied Ballistics articles, available for FREE as PDF files. There are 31 more, all available on the Applied Ballistics Articles Webpage.

Permalink - Articles, Bullets, Brass, Ammo, Reloading, Tech Tip 2 Comments »
July 5th, 2019

Optimize Bullet RPM with Berger Twist Rate Stability Calculator

Berger twist rate calculator

Berger twist rate calculatorBerger Twist-Rate Stability Calculator
On the Berger Bullets website you’ll find a handy Twist-Rate Stability Calculator that predicts your gyroscopic stability factor (SG) based on mulitiple variables: velocity, bullet length, bullet weight, barrel twist rate, ambient temperature, and altitude. This cool tool tells you if your chosen bullet will really stabilize in your barrel.


CLICK HERE to Go to TWIST RATE CALCULATOR PAGE »

How to Use Berger’s Twist Rate Calculator
Using the Twist Rate Calculator is simple. Just enter the bullet DIAMETER (e.g. .264), bullet WEIGHT (in grains), and bullet overall LENGTH (in inches). On its website, Berger conveniently provides this info for all its bullet types. For other brands, we suggest you weigh three examples of your chosen bullet, and also measure the length on three samples. Then use the average weight and length of the three. To calculate bullet stability, simply enter your bullet data (along with observed Muzzle Velocity, outside Temperature, and Altitude) and click “Calculate SG”. Try different twist rate numbers (and recalculate) until you get an SG value of 1.4 (or higher).

Gyroscopic Stability (SG) and Twist Rate
Berger’s Twist Rate Calculator provides a predicted stability value called “SG” (for “Gyroscopic Stability”). This indicates the Gyroscopic Stability applied to the bullet by spin. This number is derived from the basic equation: SG = (rigidity of the spinning mass)/(overturning aerodynamic torque).

Berger twist rate calculator

If you have an SG under 1.0, your bullet is predicted not to stabilize. If you have between 1.0 and 1.1 SG, your bullet may or may not stabilize. If you have an SG greater than 1.1, your bullet should stabilize under optimal conditions, but stabilization might not be adequate when temperature, altitude, or other variables are less-than-optimal. That’s why Berger normally recommends at least 1.5 SG to get out of the “Marginal Stability” zone.

In his book Applied Ballistics For Long-Range Shooting, Bryan Litz (Berger Ballistician) recommends at least a 1.4 SG rating when selecting a barrel twist for a particular bullet. This gives you a safety margin for shooting under various conditions, such as higher or lower altitudes or temperatures.

Story idea from EdLongrange. We welcome reader submissions.
Permalink Bullets, Brass, Ammo, Tech Tip 1 Comment »
July 2nd, 2019

Paul Phillips Crowned 2019 King of 2 Miles in New Mexico

Ko2m king two miles raton whittington center New Mexico Paul Phillips McMillan Litz ELR
Hail the King — Paul Phillips wears crown as the new 2019 King of Two Miles.

Paul Phillips, Captain of Team Global Precision Group (GPG), is the 2019 King of 2 Miles. Hail the new King! Paul won the event with a score of 48350, beating runner-up Robert Brantley who scored 46306. Fellow GPG shooter and 2017 K02M winner Derek Rodgers finished third with 38747. Phillips secured his K02M crown with good shooting in Raton, NM on both Day 1 and Day 2. On the final day, Paul had two hits at 2728 yards and one at 3166 yards. No competitor scored more than one hit at 3166 yards (1.799 miles), and no competitor scored even a single hit at the farthest target, placed at 3525 yards (2.0028 miles). So the actual 2-Mile target was never hit during the event.

Ko2m king two miles raton whittington center New Mexico Paul Phillips McMillan Litz ELR
Here are the target locations and yardages for K02M Day 2 Finals.

Ko2m king two miles raton whittington center New Mexico Paul Phillips McMillan Litz ELR
Team GPG members Derek Rodgers, Paul Phillips (center), and Mark Lonsdale with KO2M-winning rifle, K02M Trophy, $5000 Winner’s Prize from McMillan, and Nightforce Certificate.

Team Global Precision Dominates with Three of Top Four Places
Team Global Precision Group was top team overall with Paul Phillips in First Place, Derek Rodgers in Third, and Mark Lonsdale in Fourth. Team GPG, in its first world-level match together, dominated the field of 80 of the best ELR shooters in the world. First, Third, and Fourth — that’s mighty impressive gentlemen!

2019 KO2M Top 20 Results. Click on the table to see full-screen version:
Ko2m king two miles raton whittington center New Mexico Paul Phillips McMillan Litz ELR

Paul Phillips, who recently competed in the European K02M match in France, gave credit to his sponsors and team-mates: “Team GPG is honored to be … King of 2 Mile Champions. I’ve always wondered what it would feel like to be carried around on the King chair. I am humbled to be added to the list of great shooters that have been crowned before me.”

Ko2m king two miles raton whittington center New Mexico Paul Phillips McMillan Litz ELR

Paul added: “Big shout-out to all our sponsors, the match organizers, Eduardo, FCSA, and the volunteers who work so hard to make these ELR matches a major success. We’ll definitely be back in 2020!”

“Paul Phillips your win in this match is yet another example of the value of hard work paying off. I can honestly say that I don’t know anyone who works harder at ELR competition and promotion than you do. You deserve this win!” — Bryan Litz, Applied Ballistics

Equipment List for .416 Barrett 2019 KO2M-Winning Rifle

Paul’s massive KO2M rig features a BAT EX .50-Cal action with a 38″ Bartlein 1:9″-twist 5R barrel chambered for the standard .416 Barrett cartridge. The stock is a McMillan Beast One model. To tame recoil, Paul runs a T5 Terminator muzzle brake. The scope is a Nightforce 7-35x56mm ATACR F1 with MOAR Reticle. Up front is a Phoenix Precision Bipod, with an Edgewood Mini-Gator Bag in the rear. Paul is running a Bix’N Andy Comp Trigger with a 4-ounce, single-stage pull.

The complete rifle weighs 40 pounds. Bartlein did the .416 Barrett chambering using a Dave Manson reamer. Alex Sitman bedded the action in the McMillan stock as he did for the other GPG rifles. In fact, all three Team GPG rifles are essentially identical.

Load Details: Standard .416 Barrett cartridge, running .416 Caliber 550gr solid Cutting Edge Bullets at 3000 fps. The powder is Vihtavuori 20N29 ignited by RWS .50 Caliber primers. The cartridge brass is Barrett brand, produced by RUAG.

Support Gear: Ballistics are calculated with Applied Ballistics Software using velocity data from a LabRadar chronograph. Swarovski provided Team GPG with two big BTX 95 binocular spotting scopes. Phillips says “these BTX 95s really help us follow trace, spot impacts, and get on target quickly.”

Ko2m king two miles raton whittington center New Mexico Paul Phillips McMillan Litz ELR
Here are Team Applied Ballistics competitors at the 2019 KO2M event in Raton, NM. Applied Ballistics’ Mitchell Fitzpatrick posted: “[There were] some unique challenges this year, but I managed to finish in 5th place running a sub-25 pound rifle. That’s the result of a lot of our ESSO research.”

$5000 KO2M Winner’s Prize from McMillan Fiberglass Stocks

Ko2m king two miles raton whittington center New Mexico Paul Phillips McMillan Litz ELR

McMillan Fiberglass Stocks is a strong supporter of the shooting sports. Here Kelly McMillan presents Paul Phillips with a $5,000 check from McMillan Fiberglass Stocks for winning the 2019 King of 2 Mile while shooting a McMillan stock. Teammates Derek Rodgers and Mark Lonsdale also used McMillan stocks in the 2019 K02M Finals. Along with the McMillan check, Paul Phillips received $5000 from Nightforce Optics, and $1200 from Cutting Edge Bullets. Paul told us he will divide all the winnings with his team-mates because: “I won with my team — we won together.”

Ko2m king two miles raton whittington center New Mexico Paul Phillips Derek Love Team Manners Litz ELR
Derek Love competed with Team Manners Composite Stocks and took many photos. You’ll find some great 2019 K02M images on Derek’s Facebook Page.

Permalink Competition, News, Tactical 5 Comments »
June 9th, 2019

Wind Wizardry — How to Use a Kestrel Correctly

Kestrel Wind Meter Direction Vane Applied Ballistics

A lot of folks use a Kestrel Wind Meter every time at the range. That’s a good thing. However, many Kestrel owners may not be employing the Kestrel properly when seeking wind direction.

A Kestrel Wind Meter will record wind speed with its impeller wheel. However, to get the most accurate wind velocity reading, you need to have your Kestrel properly aligned with the wind direction. To find wind direction, first orient the Kestrel so that the impeller runs at minimal speed (or stops), and only then turn the BACK of the Kestrel into the wind direction. Do NOT simply rotate the Kestrel’s back panel looking for the highest wind speed reading — that’s not the correct method for finding wind direction. Rotate the side of the Kestrel into the wind first, aiming for minimal impeller movement. The correct procedure is explained below by the experts at Applied Ballistics.

How to Find the Wind Direction with a Kestrel Wind Meter

Here is the correct way to determine wind direction with a Kestrel wind meter when you have no environmental aids — no other tools than a Kestrel. (NOTE: To determine wind direction, a mounted Wind Vane is the most effective tool, but you can also look at flags, blowing grass, or even the lanyard on your Kestrel).

Step 1: Find the wind’s general direction.

Step 2: Rotate the Wind Meter 90 degrees, so that the wind is impacting the side (and not the back) of the wind meter, while still being able to see the impeller.

Step 3: Fine-tune the direction until the impeller drastically slows, or comes to a complete stop (a complete stop is preferred). If the impeller won’t come to a complete stop, find the direction which has the lowest impact on the impeller.

Step 4: Turn the BACK of the Kestrel towards the direction from which the wind is blowing. Then press the capture button, and record your wind speed.

Do NOT simply point the Kestrel’s back into the wind until you get the highest wind speed — that’s not the correct method.

Permalink Shooting Skills, Tech Tip 1 Comment »
April 29th, 2019

Wind Hack — Estimate Crosswind Deflection Without a Meter

Applied Ballistics Crosswind Estimation Wind hack G7 BC

Applied Ballistics Wind Hack

Any long range shooter knows that wind is our ultimate nemesis. The best ways of overcoming wind are to measure what we can and use computers to calculate deflection. The Applied Ballistics Kestrel is a great tool for this. As good as our tools may be, we don’t always have them at our fingertips, or they break, batteries go dead, and so on. In these cases, it’s nice to have a simple way of estimating wind based on known variables. There are numerous wind formulas of various complexity.

Applied Ballistics Crosswind Estimation Wind hack G7 BC

The Applied Ballistics (AB) Wind Hack is about the simplest way to get a rough wind solution. Here it is: You simply add 2 to the first digit of your G7 BC, and divide your drop by this number to get the 10 mph crosswind deflection. For example, suppose you’re shooting a .308 caliber 175-grain bullet with a G7 BC of 0.260 at 1000 yards, and your drop is 37 MOA. For a G7 BC of 0.260, your “wind number” is 2+2=4. So your 10 mph wind deflection is your drop (37 MOA) divided by your “wind number” (4) = 9.25 MOA. This is really close to the actual 9.37 MOA calculated by the ballistic software.

WIND HACK Formula

10 mph Cross Wind Deflection = Drop (in MOA) divided by (G7 BC 1st Digit + 2)

Give the AB wind hack a try to see how it works with your ballistics!

Some Caveats: Your drop number has to be from a 100-yard zero. This wind hack is most accurate for supersonic flight. Within supersonic range, accuracy is typically better than +/-6″. You can easily scale the 10 mph crosswind deflection by the actual wind speed. Wind direction has to be scaled by the cosine of the angle.

Permalink - Articles, Shooting Skills, Tactical 1 Comment »
April 16th, 2019

Applied Ballistics Spring Seminar — Register Now and Save

Applied Ballistics Snowbird utah spring seminar ELR

The Applied Ballistics 2019 Spring Seminar will be held at Snowbird Resort in Utah on June 1-2, 2019. The Seminar Fee is $625.00. However, now through April 21st you can use Code ABWIRE for $75 off registration. Note — Seminar fees do NOT include lodging! However, through May 4, 2019, attendees can reserve rooms at the Center-Cliff Lodge at the special seminar rate of $145.00 per night plus tax.

CLICK HERE to Register for $550 with Code ABWIRE

Primary speaker Bryan Litz will present material from his books, the Applied Ballistics Lab, and his experience shooting in various disciplines. Additional speakers addressing ballistics and long-range shooting topics will include Nick Vitalbo, Doc Beech, Alan Barnhart, Mitchell Fitzpatrick and other industry experts.

Seminar attendees will receive multiple Applied Ballistics products, all included in the registration fee:
1) Full library of Applied Ballistics Books and DVD set, valued at $275.
2) Applied Ballistics Analytics software, valued at $200.
3) Binder including hand-outs, articles, and worksheets.

Applied Ballistics Snowbird utah spring seminar ELR

Seminar Topics Will Include:

1. Trajectory Buildup – Baseline Trajectory, Gravity Drop, Vacuum Trajectory, and Aerodynamic Drag

2. Trajectory Features – Zeroing, Point Blank Range, Danger Space, and Uphill/Downhill Effects.

3. Sights – Tall Target Test (Sight Scale Factor and Cant), Aperture Sights, Turrets vs. Holding Reticles, and Extreme Adjustment for ELR.

4. Drag Modeling – What is a drag model, how is drag measured, how is a drag model used, and standard drag models.

5. Ballistic Coefficients – What is a BC, G1 and G7, Curve Fitting Challenges (averaged BCs, segmented BCs), and Estimating BCs.

6. Wind – Nature of wind, Mechanism of wind deflection (velocity scaling, lag time, wind deflection), near vs. far wind, wind measurement, terrain and vertical wind, competition Wind strategies, Wind coaching.

7. Basic Stability – Gyroscopic Stability Factor, Twist Rate Effects (muzzle velocity, precision, and BC).

8. Advanced Stability – Gyroscopic vs Dynamic Stability, Limit Cycle Yaw, Twist rate and Stability Effects in Transonic Flight, and Spin Decay.

9. Secondary Effects – Spin Drift, Coriolis, Aerodynamic Jump, Secondary Effects in Ballistic Solvers.

10. ELR Shooting – Transonic effects, Secondary Effects, Critical Nature of (Ranging, MV Measurement, Drag Modeling, Wind), Equipment Currently Being Used and Bullet Selection.

Applied Ballistics Snowbird utah spring seminar ELR

11. WEZ Analysis – What is WEZ, Confidence Environments, Precision (Wind, Range, MV), Accuracy (Sights, Trajectory Modeling, Secondary Effects, Calibration (Trueing)).

12. Ballistic Solvers – Components (Interface, Solver/Simulation, Model), Potential Accuracy, and walk-through of use with technical explanation of inputs.

13. Other Topics – Technology, Laser RangeFinders, Non-Linear Divergence, and Much More.

Permalink Shooting Skills, Tech Tip No Comments »
March 27th, 2019

Accuracy vs. Precision — Litz Explains the Difference

Applied Ballistics Rounds on Target DVD accurateshooter.com

The NSSF has posted a video featuring Bryan Litz of Applied Ballistics. Bryan also serves as Chief Ballistician for Berger Bullets and ABM Ammo. In this short video, Bryan explains the importance of ballistics for precision shooting at long range. Bryan covers key elements — drop, wind drift, angle correction and more. And Bryan also explains the key difference between Accuracy and Precision.

The principles Bryan discusses are covered (in greater detail) in the Putting Rounds on Target instructional DVD set. This 3-Disc collection boasts a total run-time of 3 hours and 37 minutes. The three DVDs, with many graphics and video segments, deliver as much information as a weekend shooting seminar… at a fraction of the cost. The 3-DVD set sells for $44.95.

Applied Ballistics Rounds on Target DVD accurateshooter.com

Disc 1

• Accuracy & Precision
• Tall Target Test
• Chronographs & Statistics
• Ballistic Coefficient
• Trajectory Terms
• Run Time: 1 hour, 4 min

Disc 2

• Primary Elevation (Wind)
• Secondary Effects
• Using Ballistics Solvers
• Short & LR Equipment
• Run Time: 1 hour, 11 min

Disc 3

• On The Range: .308 Win
• On The Range: .284 Win
• On The Range: .338 LM
• Extended Range Shooting
• One Mile Shooting
• Run Time: 1 hour, 22 min

DVD Applied Ballistics Bryan Litz Shooting F-Class .284 Win .338 LM

Permalink Bullets, Brass, Ammo, Shooting Skills, Tech Tip No Comments »
March 26th, 2019

Angular Measurement — Mil vs. MOA — What You Need to Know

Mil MOA reticle ranging PRS tactical minute angle precision rifle series
Visit PrecisionRifleBlog.com for a discussion of MIL vs. MOA.

Many guys getting started in long range shooting are confused about what kind of scope they should buy — specifically whether it should have MIL-based clicks or MOA-based clicks. Before you can make that decision, you need to understand the terminology. This article, with a video by Bryan Litz, explains MILS and MOA so you can choose the right type of scope for your intended application.

This March-FX 5-40x56mm Tactical FFP scope features 0.05 MIL Clicks.
Mil MOA reticle ranging PRS tactical minute angle precision rifle series

You probably know that MOA stands for “Minute of Angle” (or more precisely “minute of arc”), but could you define the terms “Milrad” or “MIL”? In his latest video, Bryan Litz of Applied Ballitics explains MOA and MILs (short for “milliradians”). Bryan defines those terms and explains how they are used. One MOA is an angular measurement (1/60th of one degree) that subtends 1.047″ at 100 yards. One MIL (i.e. one milliradian) subtends 1/10th meter at 100 meters; that means that 0.1 Mil is one centimeter (1 cm) at 100 meters. Is one angular measurement system better than another? Not necessarily… Bryan explains that Mildot scopes may be handy for ranging, but scopes with MOA-based clicks work just fine for precision work at known distances. Also because one MOA is almost exactly one inch at 100 yards, the MOA system is convenient for expressing a rifle’s accuracy. By common parlance, a “half-MOA” rifle can shoot groups that are 1/2-inch (or smaller) at 100 yards.

What is a “Minute” of Angle?
When talking about angular degrees, a “minute” is simply 1/60th. So a “Minute of Angle” is simply 1/60th of one degree of a central angle, measured either up and down (for elevation) or side to side (for windage). At 100 yards, 1 MOA equals 1.047″ on the target. This is often rounded to one inch for simplicity. Say, for example, you click up 1 MOA (four clicks on a 1/4-MOA scope). That is roughly 1 inch at 100 yards, or roughly 4 inches at 400 yards, since the target area measured by an MOA subtension increases with the distance.

one MOA minute of angle diagram

MIL vs. MOA for Target Ranging
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.”

READ MIL vs. MOA Cal Zant Article.

Permalink - Articles, - Videos, Shooting Skills 6 Comments »
March 10th, 2019

Tall Target Test — How to Verify Your Scope’s True Click Values

Scope Click Verify Elevation Tall Target Bryan Litz NSSF test turret MOA MIL

Have you recently purchased a new scope? Then you should verify the actual click value of the turrets before you use the optic in competition (or on a long-range hunt). While a scope may have listed click values of 1/4-MOA, 1/8-MOA or 0.1 Mils, the reality may be slightly different. Many scopes have actual click values that are slightly higher or lower than the value claimed by the manufacturer. The small variance adds up when you click through a wide range of elevation.

In this video, Bryan Litz of Applied Ballistics shows how to verify your true click values using a “Tall Target Test”. The idea is to start at the bottom end of a vertical line, and then click up 30 MOA or so. Multiply the number of clicked MOA by 1.047 to get the claimed value in inches. For example, at 100 yards, 30 MOA is exactly 31.41 inches. Then measure the difference in your actual point of impact. If, for example, your point of impact is 33 inches, then you are getting more than the stated MOA with each click (assuming the target is positioned at exactly 100 yards).

Scope Click Verify Elevation Tall Target Bryan Litz NSSF test turret MOA MIL

How to Perform the Tall Target Test
The objective of the tall target test is to insure that your scope is giving you the proper amount of adjustment. For example, when you dial 30 MOA, are you really getting 30 MOA, or are you getting 28.5 or 31.2 MOA? The only way to be sure is to verify, don’t take it for granted! Knowing your scopes true click values insures that you can accurately apply a ballistic solution. In fact, many perceived inaccuracies of long range ballistics solutions are actually caused by the scopes not applying the intended adjustment. In order to verify your scope’s true movement and calculate a correction factor, follow the steps in the Tall Target Worksheet. This worksheet takes you thru the ‘calibration process’ including measuring true range to target and actual POI shift for a given scope adjustment. The goal is to calculate a correction factor that you can apply to a ballistic solution which accounts for the tracking error of your scope. For example, if you find your scope moves 7% more than it should, then you have to apply 7% less than the ballistic solution calls for to hit your target.


CLICK HERE to DOWNLOAD Tall Target Worksheet (PDF) »

NOTE: When doing this test, don’t go for the maximum possible elevation. You don’t want to max out the elevation knob, running it to the top stop. Bryan Litz explains: “It’s good to avoid the extremes of adjustment when doing the tall target test.I don’t know how much different the clicks would be at the edges, but they’re not the same.”

Should You Perform a WIDE Target Test Too?
What about testing your windage clicks the same way, with a WIDE target test? Bryan Litz says that’s not really necessary: “The wide target test isn’t as important for a couple reasons. First, you typically don’t dial nearly as much wind as you do elevation. Second, your dialed windage is a guess to begin with; a moving average that’s different for every shot. Whereas you stand to gain a lot by nailing vertical down to the click, the same is not true of windage. If there’s a 5% error in your scope’s windage tracking, you’d never know it.”

Scope Tall Test level calibrationVerifying Scope Level With Tall Target Test
Bryan says: “While setting up your Tall Target Test, you should also verify that your scope level is mounted and aligned properly. This is critical to insuring that you’ll have a long range horizontal zero when you dial on a bunch of elevation for long range shots. This is a requirement for all kinds of long range shooting. Without a properly-mounted scope level (verified on a Tall Target), you really can’t guarantee your horizontal zero at long range.”

NOTE: For ‘known-distance’ competition, this is the only mandatory part of the tall target test, since slight variations in elevation click-values are not that important once you’re centered “on target” at a known distance.

Permalink Optics, Tech Tip No Comments »
February 26th, 2019

Big Bullets — Applied Ballistics Tests 379gr .375 Cal Berger Solids

Berger 379 grain 379gr solid bullet .375 caliber enabler

Berger Bullets has created some impressive solid bullets for Extreme Long Range (ELR) shooting. These ultra-long, lathe-turned solids were unveiled at SHOT Show 2019, and they should reach Berger dealers by Mid-April this year. To test their consistency and develop refined BC numbers, the Applied Ballistics test team has braved cold winter weather to test Berger’s new 379 grain solids. The results have been impressive.

Berger 379 grain 379gr solid bullet .375 caliber enabler
Bryan Litz, Applied Ballistics founder, tests 379gr Bergers in .375 EnABLER rounds.

The Applied Ballistics testers have loaded the new Berger solids in an innovative .375-Caliber cartridge called the .375 EnABELR. This is slightly shorter than a .375 CheyTac so it allows the round to mag-feed. The brass is made by Peterson. The testers report: “We’ve been loading and shooting a pile of .375 EnABELR this month. The Berger 379gr Solids are proving to be incredibly consistent. Here’s a 10-shot string for one of our guns, shots number 931-940.”

Berger 379 grain 379gr solid bullet .375 caliber enabler

The .375 EnABELR is achieving impressive velocities — 2990 FPS — with the 379-grainers from a 30″ barrel. The test team states: “We’ve been shooting [a 30″-long] 1:7″ twist which works good, but are going to try some 1:8″ and 1:9″ also”.

Berger 379 grain 379gr solid bullet .375 caliber enabler

The .375 EnABELR Cartridge — Big and Fast
The .375 EnABELR cartridge was designed to offer .375 CheyTac performance in a slightly shorter package: “The problem with the .375 CheyTac is that, when loaded with the highest performance .375 caliber bullets (379-407 gr Berger Solids, and the 400-425 grain Cutting Edge Lazers) the round is not magazine feed-able in any action that’s sized for CheyTac cartridges.

Berger 379 grain 379gr solid bullet .375 caliber enabler

“Knowing the .375 CheyTac produced substantial performance, and that it was just too long for magazine feeding, made it easy to converge on a design for the .375 EnABELR. We just had to make the case short enough to achieve magazine length with the desired bullets, while adding a little more diameter to keep the case capacity similar to the .375 CheyTac. The resulting basic shape is quite similar in proportions to the successful .338 Norma Magnum Cartridge which, interestingly, was selected as the cartridge for General Dynamics Lightweight Medium Machine Gun (LWMMG).”

Brass Source — Purchase the Peterson-made .338 EnABELR and .375 EnABELR brass through the Applied Ballistics WebStore. Price for both .338 EnABELR and .375 EnABELR is $125.00 for 50 cases.

Berger 379 grain 379gr solid bullet .375 caliber enabler

Permalink Bullets, Brass, Ammo, Gear Review, New Product, Tactical 2 Comments »
February 22nd, 2019

MV on the Box? Why You Still Need to Chron Factory Ammo

muzzle velocity applied Ballistics MV chronograph

Why You CANNOT Rely on the MV Printed on the Ammo Box!
When figuring out your come-ups with a ballistics solver or drop chart it’s “mission critical” to have an accurate muzzle velocity (MV). When shooting factory ammo, it’s tempting to use the manufacturer-provided MV which may be printed on the package. That’s not such a great idea says Bryan Litz of Applied Ballistics. Don’t rely on the MV on the box, Bryan advises — you should take out your chrono and run your own velocity tests. There are a number of reasons why the MV values on ammo packaging may be inaccurate. Below is a discussion of factory ammo MV from the Applied Ballistics Facebook Page.

Five Reasons You Cannot Trust the Velocity on a Box of Ammo:

1. You have no idea about the rifle used for the MV test.

2. You have no idea what atmospheric conditions were during testing, and yes it matters a lot.

3. You have no idea of the SD for the factory ammo, and how the manufacturer derived the MV from that SD. (Marketing plays a role here).

4. You have no idea of the precision and quality of chronograph(s) used for velocity testing.

5. You have no idea if the manufacturer used the raw velocity, or back-calculated the MV. The BC used to back track that data is also unknown.

1. The factory test rifle and your rifle are not the same. Aside from having a different chamber, and possibly barrel length some other things are important too like the barrel twist rate, and how much wear was in the barrel. Was it just recently cleaned, has it ever been cleaned? You simply don’t know anything about the rifle used in testing.

2. Temperature and Humidity conditions may be quite different (than during testing). Temperature has a physical effect on powder, which changes how it burns. Couple this with the fact that different powders can vary in temp-stability quite a bit. You just don’t know what the conditions at the time of testing were. Also a lot of factory ammunition is loaded with powder that is meter friendly. Meter friendly can often times be ball powder, which is less temperature stable than stick powder often times.

3. The ammo’s Standard Deviation (SD) is unknown. You will often notice that while MV is often listed on ammo packages, Standard Deviation (normally) is not. It is not uncommon for factory ammunition to have an SD of 18 or higher. Sometimes as high as 40+. As such is the nature of metering powder. With marketing in mind, did they pick the high, low, or average end of the SD? We really don’t know. You won’t either until you test it for yourself. For hand-loaded ammo, to be considered around 10 fps or less. Having a high SD is often the nature of metered powder and factory loads. The image below is from Modern Advancements in Long Range Shooting: Volume II.

muzzle velocity applied Ballistics MV chronograph

4. You don’t know how MV was measured. What chronograph system did the manufacturer use, and how did they back track to a muzzle velocity? A chronograph does not measure true velocity at the muzzle; it simply measures velocity at the location it is sitting. So you need to back-calculate the distance from the chrono to the end of the barrel. This calculation requires a semi-accurate BC. So whose BC was used to back track to the muzzle or did the manufacturer even do that? Did they simply print the numbers displayed by the chronograph? What kind of chronograph setup did they use? We know from our Lab Testing that not all chronographs are created equal. Without knowing what chronograph was used, you have no idea the quality of the measurement. See: Applied Ballistics Chronograph Chapter Excerpt.

5. The MV data may not be current. Does the manufacturer update that data for every lot? Or is it the same data from years ago? Some manufacturers rarely if ever re-test and update information. Some update it every lot (ABM Ammo is actually tested every single lot for 1% consistency). Without knowing this information, you could be using data for years ago.

CONCLUSION: Never use the printed MV off a box of ammo as anything more than a starting point, there are too many factors to account for. You must always either test for the MV with a chronograph, or use carefully obtained, live fire data. When you are using a Ballistic Solver such as the AB Apps or Devices integrated with AB, you need to know the MV to an accuracy down to 5 fps. The more reliable the MV number, the better your ballistics solutions.

Permalink Bullets, Brass, Ammo, Shooting Skills, Tech Tip 1 Comment »
February 21st, 2019

First Shot Hit at 1500 Yards — Could You Do That?

6.5 Creedmoor 1500 yards Kestrel
File photo showing Kestrel 5700 Elite. See video below for 6.5 Creedmoor rifle.

6.5 Creedmoor 1500 yards applied ballistics kestrelIt’s not easy to place a first shot on target at 1500 yards. You must measure the wind speed with precision, know your exact muzzle velocity, and have a sophisticated ballistics solver. In this short video from Ryansrangereport.com, the shooter manages a first-round hit on a steel silhouette at 1500 yards. He used a Kestrel 4500 NV Weather Meter with Applied Ballistics software to figure out the trajectory for his 6.5 Creedmoor rounds.

The Kestrel recorded a wind velocity, and the internal software calculated a solution of 17 Mils elevation (that’s 928 inches of drop) with 2.5 Mils windage. “Bang” — the shooter sends it, and 2.6 seconds later “Clang” he had a hit (flight time was 2.6 seconds). Bryan Litz observes: “This is the science of accuracy (in the form of an Applied Ballistics Kestrel) being put to good use at 1500 yards”.

Later in the video (1:05-1:15) the shooter places three rounds on steel at 1000 yards in just 10 seconds. The three shots all fall within 10″ or so — pretty impressive for rapid fire. The shooter reports: “[In my 6.5 Creedmoor] I’m using a 136gr Lapua Scenar L. This bullet has impressed me. It screams out of my barrel at 2940 fps and holds on all the way out to 1,500 yards.”

The rifle was built by Aaron Roberts of Roberts Precision Rifles (RPRifles.com). Chambered for the 6.5 Creedmoor, it features a Leupold Mark VI 3-18x44mm scope.

Roberts Precision Rifles
19515 Wied Rd. Suite D
Spring, Texas 77388
Phone: 281-651-5593
Email: rprifles @ gmail.com

Permalink Shooting Skills, Tactical 1 Comment »
February 12th, 2019

How to Avoid a Train Wreck at the Berger SW Nationals

train wreck Bryan Litz shooting tips ballistics

Today is Day One of the Berger Southwest Nationals, at the Ben Avery Range outside Phoenix, AZ. There will be a 600-yard mid-range match. Many of the nation’s most talented F-Class and sling shooters will be there. But no matter what your skill level, it is still possible to make major mistakes, that can spoil the day and/or put you out of the running for the entire match.

Berger SW Nationals mid-range match
Photo by Sherri Jo Gallagher.

Berger SW Nationals mid-range match

In any shooting competition, you must try to avoid major screw-ups that can ruin your day (or your match). In this article, past F-TR National Mid-Range and Long Range Champion Bryan Litz talks about “Train Wrecks”, i.e. those big disasters (such as equipment failures) that can ruin a whole match. Bryan illustrates the types of “train wrecks” that commonly befall competitors, and he explains how to avoid these “unmitigated disasters”.

Urban Dictionary “Train Wreck” Definition: “A total @#$&! disaster … the kind that makes you want to shake your head.”

train wreck Bryan Litz shooting tips ballisticsTrain Wrecks (and How to Avoid Them)
by Bryan Litz of Applied Ballistics LLC.

Success in long range competition depends on many things. Those who aspire to be competitive are usually detail-oriented, and focused on all the small things that might give them an edge. Unfortunately it’s common for shooters lose sight of the big picture — missing the forest for the trees, so to speak.

Consistency is one of the universal principles of successful shooting. The tournament champion is the shooter with the highest average performance over several days, often times not winning a single match. While you can win tournaments without an isolated stellar performance, you cannot win tournaments if you have a single train wreck performance. And this is why it’s important for the detail-oriented shooter to keep an eye out for potential “big picture” problems that can derail the train of success!

Train wrecks can be defined differently by shooters of various skill levels and categories. Anything from problems causing a miss, to problems causing a 3/4-MOA shift in wind zero can manifest as a train wreck, depending on the kind of shooting you’re doing.

Berger SW Nationals
Photo by Sherri Jo Gallagher.

Below is a list of common Shooting Match Train Wrecks, and suggestions for avoiding them.

1. Cross-Firing. The fastest and most common way to destroy your score (and any hopes of winning a tournament) is to cross-fire. The cure is obviously basic awareness of your target number on each shot, but you can stack the odds in your favor if you’re smart. For sling shooters, establish your Natural Point of Aim (NPA) and monitor that it doesn’t shift during your course of fire. If you’re doing this right, you’ll always come back on your target naturally, without deliberately checking each time. You should be doing this anyway, but avoiding cross-fires is another incentive for monitoring this important fundamental. In F-Class shooting, pay attention to how the rifle recoils, and where the crosshairs settle. If the crosshairs always settle to the right, either make an adjustment to your bipod, hold, or simply make sure to move back each shot. Also consider your scope. Running super high magnification can leave the number board out of the scope’s field view. That can really increase the risk of cross-firing.

2. Equipment Failure. There are a wide variety of equipment failures you may encounter at a match, from loose sight fasteners, to broken bipods, to high-round-count barrels that that suddenly “go south” (just to mention a few possibilities). Mechanical components can and do fail. The best policy is to put some thought into what the critical failure points are, monitor wear of these parts, and have spares ready. This is where an ounce of prevention can prevent a ton of train wreck. On this note, if you like running hot loads, consider whether that extra 20 fps is worth blowing up a bullet (10 points), sticking a bolt (DNF), or worse yet, causing injury to yourself or someone nearby.

train wreck Bryan Litz shooting tips ballistics

[Editor’s Note: The 2016 F-Class Nationals will employ electronic targets so conventional pit duties won’t be required. However, the following advice does apply for matches with conventional targets.]

3. Scoring/Pit Malfunction. Although not related to your shooting technique, doing things to insure you get at least fair treatment from your scorer and pit puller is a good idea. Try to meet the others on your target so they can associate a face with the shooter for whom they’re pulling. If you learn your scorer is a Democrat, it’s probably best not to tell Obama jokes before you go for record. If your pit puller is elderly, it may be unwise to shoot very rapidly and risk a shot being missed (by the pit worker), or having to call for a mark. Slowing down a second or two between shots might prevent a 5-minute delay and possibly an undeserved miss.

train wreck Bryan Litz shooting tips ballistics4. Wind Issues. Tricky winds derail many trains. A lot can be written about wind strategies, but here’s a simple tip about how to take the edge off a worse case scenario. You don’t have to start blazing away on the command of “Commence fire”. If the wind is blowing like a bastard when your time starts, just wait! You’re allotted 30 minutes to fire your string in long range slow fire. With average pit service, it might take you 10 minutes if you hustle, less in F-Class. Point being, you have about three times longer than you need. So let everyone else shoot through the storm and look for a window (or windows) of time which are not so adverse. Of course this is a risk, conditions might get worse if you wait. This is where judgment comes in. Just know you have options for managing time and keep an eye on the clock. Saving rounds in a slow fire match is a costly and embarrassing train wreck.

5. Mind Your Physical Health. While traveling for shooting matches, most shooters break their normal patterns of diet, sleep, alcohol consumption, etc. These disruptions to the norm can have detrimental effects on your body and your ability to shoot and even think clearly. If you’re used to an indoor job and eating salads in air-conditioned break rooms and you travel to a week-long rifle match which keeps you on your feet all day in 90-degree heat and high humidity, while eating greasy restaurant food, drinking beer and getting little sleep, then you might as well plan on daily train wrecks. If the match is four hours away, rather than leaving at 3:00 am and drinking five cups of coffee on the morning drive, arrive the night before and get a good night’s sleep.”

Keep focused on the important stuff. You never want to lose sight of the big picture. Keep the important, common sense things in mind as well as the minutia of meplat trimming, weighing powder to the kernel, and cleaning your barrel ’til it’s squeaky clean. Remember, all the little enhancements can’t make up for one big train wreck!

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January 31st, 2019

Common Misconceptions about Twist Rate and Stabilization

FirearmsID.com barrel rifling diagram

Understanding Twist: Bullet Stabilization

by Sierra Bullets Ballistic Technician Paul Box for Sierra Bullets Blog.

Based on the questions we get on a daily basis on our 800 (Customer Support) line, twist is one of the most misunderstood subjects in the gun field. So let’s look deeper into this mystery and get a better understanding of what twist really means.

When you see the term 1:14″ (1-14) or 1:9″ twist, just exactly what does this mean? A rifle having a 1:14″ twist means the bullet will rotate one complete revolution every fourteen inches of the barrel. Naturally a 1:9″ turns one time every nine inches that it travels down the barrel. Now, here’s something that some people have trouble with. I’ve had calls from shooters thinking that a 1:14″ twist was faster than a 1:9″ because the number was higher with the 1:14″. The easiest way to remember this is the higher the number, the slower the twist rate is.

Now, the biggest misconception is that if a shooter has a .223 with a 1:8″ twist, his rifle won’t stabilize a 55gr bullet or anything lighter. So let’s look at what is required. The longer a bullet is for its diameter, the faster the twist has to be to stabilize it. In the case of the .223 with a 1:8″ twist, this was designed to stabilize 80gr bullets in this diameter. In truth the opposite is true. A 1:8″ will spin a 55gr faster than what is required in order to stabilize that length of bullet. If you have a bullet with good concentricity in its jacket, over-spinning it will not [normally] hurt its accuracy potential. [Editor’s Note: In addition, the faster twist rate will not, normally, decrease velocity significantly. That’s been confirmed by testing done by Bryan Litz’s Applied Ballistics Labs. There may be some minor speed loss.]

FirearmsID.com barrel rifling diagram
Many barrel-makers mark the twist rate and bore dimensions on their barrel blanks.

Think of it like tires on your truck. If you have a new set of tires put on your truck, and they balance them proper at the tire shop, you can drive down a street in town at 35 MPH and they spin perfect. You can get out on the highway and drive 65 MPH and they still spin perfect. A bullet acts the same way.

Once I loaded some 35gr HP bullets in a 22-250 Ackley with a 1:8″ twist. After putting three shots down range, the average velocity was 4584 FPS with an RPM level of 412,560. The group measured .750″ at 100 yards. This is a clear example that it is hard to over-stabilize a good bullet.

Twist-rate illustration by Erik Dahlberg courtesy FireArmsID.com. Krieger barrel photo courtesy GS Arizona.
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January 24th, 2019

How to Calculate Bullet RPM — Spin Rates and Stability

Spin rate stability bullet speed RPM Formula stabilization barrel twist
Photo by Werner Mehl, www.kurzzeit.com, all rights reserved.

Most serious shooters can tell you the muzzle velocity (MV) of their ammunition, based on measurements taken with a chronograph, or listed from a manufacturer’s data sheet. (Of course, actual speed tests conducted with YOUR gun will be more reliable.)

Bullet RPM = MV X 720/Twist Rate (in inches)

However, if you ask a typical reloader for the rotational rate of his bullet, in revolutions per minute (RPM), chances are he can’t give you an answer.

Knowing the true spin rate or RPM of your bullets is very important. First, spin rate, or RPM, will dramatically affect the performance of a bullet on a game animal. Ask any varminter and he’ll tell you that ultra-high RPM produces more dramatic hits with more “varmint hang time”. Second, RPM is important for bullet integrity. If you spin your bullets too fast, this heats up the jackets and also increases the centrifugal force acting on the jacket, pulling it outward. The combination of heat, friction, and centrifugal force can cause jacket failure and bullet “blow-ups” if you spin your bullets too fast.

Accuracy and RPM
Additionally, bullet RPM is very important for accuracy. Nearly all modern rifles use spin-stablized bullets. The barrel’s rifling imparts spin to the bullet as it passes through the bore. This rotation stabilizes the bullet in flight. Different bullets need different spin rates to perform optimally. Generally speaking, among bullets of the same caliber, longer bullets need more RPM to stabilize than do shorter bullets–often a lot more RPM.

It is generally believed that, for match bullets, best accuracy is achieved at the minimal spin rates that will fully stabilize the particular bullet at the distances where the bullet must perform. That’s why short-range 6PPC benchrest shooters use relatively slow twist rates, such as 1:14″, to stabilize their short, flatbase bullets. They could use “fast” twist rates such as 1:8″, but this delivers more bullet RPM than necessary. Match results have demonstrated conclusively that the slower twist rates produce better accuracy with these bullets.

On the other hand, Research by Bryan Litz of Applied Ballistics has shown that with long, boat-tailed bullets, best accuracy may be achieved with twist rates slightly “faster” than the minimum required for stabilization. The reasons for this are somewhat complex — but it’s something to consider when you buy your next barrel. If, for example, the bullet-maker recommends a 1:8.25″ twist, you might want to get a true 1:8″-twist barrel.

Calculating Bullet RPM from MV and Twist Rate
The lesson here is that you want to use the optimal RPM for each bullet type. So how do you calculate that? Bullet RPM is a function of two factors, barrel twist rate and velocity through the bore. With a given rifling twist rate, the quicker the bullet passes through the rifling, the faster it will be spinning when it leaves the muzzle. To a certain extent, then, if you speed up the bullet, you can use a slower twist rate, and still end up with enough RPM to stabilize the bullet. But you have to know how to calculate RPM so you can maintain sufficient revs.

Bullet RPM Formula
Here is a simple formula for calculating bullet RPM:

MV x (12/twist rate in inches) x 60 = Bullet RPM

Quick Version: MV X 720/Twist Rate = RPM

Example One: In a 1:12″ twist barrel the bullet will make one complete revolution for every 12″ (or 1 foot) it travels through the bore. This makes the RPM calculation very easy. With a velocity of 3000 feet per second (FPS), in a 1:12″ twist barrel, the bullet will spin 3000 revolutions per SECOND (because it is traveling exactly one foot, and thereby making one complete revolution, in 1/3000 of a second). To convert to RPM, simply multiply by 60 since there are 60 seconds in a minute. Thus, at 3000 FPS, a bullet will be spinning at 3000 x 60, or 180,000 RPM, when it leaves the barrel.

Example Two: What about a faster twist rate, say a 1:8″ twist? We know the bullet will be spinning faster than in Example One, but how much faster? Using the formula, this is simple to calculate. Assuming the same MV of 3000 FPS, the bullet makes 12/8 or 1.5 revolutions for each 12″ or one foot it travels in the bore. Accordingly, the RPM is 3000 x (12/8) x 60, or 270,000 RPM.

Implications for Gun Builders and Reloaders
Calculating the RPM based on twist rate and MV gives us some very important information. Number one, we can tailor the load to decrease velocity just enough to avoid jacket failure and bullet blow-up at excessive RPMs. Number two, knowing how to find bullet RPM helps us compare barrels of different twist rates. Once we find that a bullet is stable at a given RPM, that gives us a “target” to meet or exceed in other barrels with a different twist rate. Although there are other important factors to consider, if you speed up the bullet (i.e. increase MV), you MAY be able to run a slower twist-rate barrel, so long as you maintain the requisite RPM for stabilization and other factors contributing to Gyroscopic Stability are present. In fact, you may need somewhat MORE RPM as you increase velocity, because more speed puts more pressure, a destabilizing force, on the nose of the bullet. You need to compensate for that destabilizing force with somewhat more RPM. But, as a general rule, if you increase velocity you CAN decrease twist rate. What’s the benefit? The slower twist-rate barrel may, potentially, be more accurate. And barrel heat and friction may be reduced somewhat.

Just remember that as you reduce twist rate you need to increase velocity, and you may need somewhat MORE RPM than before. (As velocities climb, destabilizing forces increase somewhat, RPM being equal.) There is a formula by Don Miller that can help you calculate how much you can slow down the twist rate as you increase velocity.

CLICK HERE for Miller Formula in Excel Spreadsheet Format

That said, we note that bullet-makers provide a recommended twist rate for their bullets. This is the “safe bet” to achieve stabilization with that bullet, and it may also indicate the twist rate at which the bullet shoots best. Though the RPM number alone does not assure gyroscopic stability, an RPM-based calculation can be very useful. We’ve seen real world examples where a bullet that needs an 8-twist barrel at 2800 FPS MV, would stabilize in a 9-twist barrel at 3200 FPS MV. Consider these examples.

MV = 2800 FPS
8-Twist RPM = 2800 x (12/8) x 60 = 252,000 RPM

MV = 3200 FPS
9-Twist RPM = 3200 x (12/9) x 60 = 256,000 RPM

Of course max velocity will be limited by case capacity and pressure. You can’t switch to a slower twist-rate barrel and maintain RPM if you’ve already maxed out your MV. But the Miller Formula can help you select an optimal twist rate if you’re thinking of running the same bullet in a larger case with more potential velocity.

Permalink Bullets, Brass, Ammo, Gunsmithing, Tech Tip 1 Comment »
January 14th, 2019

Wind-Reading Tips from Champion Shooters

Shooting Sports USA

The digital archives of Shooting Sports USA magazine (SSUSA) features an Expert Forum on Wind Reading. This outstanding article on wind reading starts off with a section by ballistics guru Bryan Litz, author of Applied Ballistics for Long-Range Shooting. Then four of the greatest American shooters in history share their personal wind wisdom. Lanny Basham (Olympic Gold Medalist, author, Winning in the Wind), Nancy Tompkins (Past National HP Champion, author, Prone and Long-Range Rifle Shooting), David Tubb (11-Time Camp Perry National Champion), and Lones Wigger (Olympic Hall of Fame) all offer practical wind-reading lessons learned during their shooting careers.

CLICK HERE for Full Article in Shooting Sports USA Archive

CLICK HERE to Download Article Issue in Printable PDF Format.

Whether you shoot paper at Perry or prairie dogs in the Dakotas, this is a certified “must-read” resource on reading the wind. Here is a sample selection from the article:

Shooting Sports USA



Visit www.SSUSA.org

Shooting Sports USA magazine (SSUSA) has a modern, mobile-friendly website with tons of great content. Log on to www.ssusa.org. There you’ll find current news stories as well as popular articles from the SSUSA archives. The SSUSA website also includes match reports, gear reviews, reloading advice, plus expert marksmanship tips from the USAMU.

Permalink - Articles, Shooting Skills 5 Comments »
January 2nd, 2019

Accuracy Vs. Precision — They Are Not the Same Thing

Applied Ballistics Accuracy Precision
This image is from Modern Advancements in Long Range Shooting, Volume 2.

The next time a shooter comes up to you at the range, and says: “My rifle shoots one-third MOA all day long”, challenge him to put a first-round hit on a 1/2 MOA plate at 1000 yards. There’s a difference between shooting small groups at close range (Precision) and “on-target” Accuracy at long range.

Article by Applied Ballistics, LLC
Just how much better is a 0.5 MOA rifle vs. a 1 MOA rifle? Is it worth chasing quarter-MOA if you have half-MOA rifle? This is an important question. If you look across Facebook you will find scores of shooters posting 1/3-MOA or 1/4-MOA shot groups [usually at 100 yards]. Some of those guys are spending countless hours trying to chase that golden quarter-MOA group.

Don’t take this statement the wrong way, having a good, consistent rifle is a key to success. But accuracy is extremely important to long range shooting. Having a precision (0.5 MOA) rifle, but not having put the time in to practice accuracy (hitting a 0.5 MOA plate first shot at 1000 yards) is counter-productive. [Editor: By this, we mean that you can have a rifle capable of shooting small groups at 100 yards, but you won’t see that gun’s full potential unless you can practice and perfect the skills of long-range shooting. Successful long range shooting demands more than precision alone.]

What if, your goal was to produce 5-shot, sub-half-MOA groups at 1000 yards instead of 100 yards? Think about how much more you would be including in the learning process, especially that all-important factor: managing the wind! Here is a good article that talks about Precision vs. Accuracy: Hitting Targets at Long Range.

This is not intended to say that precision is not important; rather it is intended to show that balance is important. You can use WEZ to do your own studies on this very subject, and it might be surprising to the shooter just how much you don’t gain by chasing precision over accuracy. Two books which cover this subject really well are Accuracy and Precision for Long Range Shooting and Modern Advancements in Long Range Shooting Vol 2.

Here’s a stunning combination of Precision (small group) WITH accuracy (centered on target). Yep that’s ten shots at 1000 yards, all in the middle of the target:
Scott Nix Dasher Record

Video Demonstrates Amazing 1000-Yard Accuracy AND Precision

Watch the video. You can see the group form up, shot by shot. It’s pretty amazing. Scott’s first shot (at the 45-second mark of the video) was right in the X-Ring, and four of Scott’s first five shots were Xs. That’s drilling them!

Comments

“Accuracy with precision is the route for me. It is not an either/or game. If I have a precision rifle (0.25 MOA or less) and I practice to be accurate, then high scores will be the result — Jim Borden

“I would agree for PRS, hunting, and to a certain extent F-Class. However, for 1000-yard IBS benchrest competition, 0.5 MOA groups in good conditions will almost always loose the relay.” — James B

“Another thought is that [at 1000 yards] a 1 MOA gun with single-digit standard deviations [may] out shoot a 0.5 MOA rifle with standard deviations of 20+ fps.” — Beard Owens

“Both… you need both: Accuracy AND Precision. I competed in varmint matches — we shot small silhouettes at 600 yards. I started with a factory .260 Rem rifle that was 0.8 MOA on a good day. I typically hit 8-9 of 20 targets, but rarely nailed the small chickens — which had a hit zone just 4″ in diameter. I then started using a semi-custom 6mmBR rifle that could reliably deliver 1/4 MOA at 100 yards (honest). My hit count on the silhouettes zoomed to 15-18, and suddenly the chickens were going down. In that game — small targets at 600 yards — there was no substitute for precision.” — Paul McM

Permalink Competition, News, Shooting Skills 2 Comments »
December 16th, 2018

G1 vs. G7 Ballistic Coefficient Models — What You Need to Know

G1 G7 BC drag models

Over the past 12 months, this article was one of the TOP TEN most-read Daily Bulletin features. We’re reprising it today for those who may have missed it the first time. The above diagram comes from a TiborasurasRex YouTube Video comparing G1 and G7 BC models. CLICK HERE to watch the video.

The better, up-to-date ballistics programs let you select either G1 or G7 Ballistic Coefficient (BC) values when calculating a trajectory. The ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. You’ve probably seen that G7 values are numerically lower than G1 values for the same bullet (typically). But that doesn’t mean you should select a G1 value simply because it is higher.

Some readers are not quite sure about the difference between G1 and G7 models. One forum member wrote us: “I went on the JBM Ballistics website to use the web-based Trajectory Calculator and when I got to the part that gives you a choice to choose between G1 and G7 BC, I was stumped. What determines how, or which one to use?”

The simple answer is the G1 value normally works better for shorter flat-based bullets, while the G7 value should work better for longer, boat-tailed bullets.

G1 vs. G7 Ballistic Coefficients — Which Is Right for You?
G1 and G7 refer both refer to aerodynamic drag models based on particular “standard projectile” shapes. The G1 shape looks like a flat-based bullet. The G7 shape is quite different, and better approximates the geometry of a modern long-range bullet. So, when choosing your drag model, G1 is preferrable for flat-based bullets, while G7 is ordinarily a “better fit” for longer, boat-tailed bullets.

G1 G7 Ballistic coefficients

Drag Models — G7 is better than G1 for Long-Range Bullets
Many ballistics programs still offer only the default G1 drag model. Bryan Litz, author of Applied Ballistics for Long Range Shooting, believes the G7 standard is preferrable for long-range, low-drag bullets: “Part of the reason there is so much ‘slop’ in advertised BCs is because they’re referenced to the G1 standard which is very speed sensitive. The G7 standard is more appropriate for long range bullets. Here’s the results of my testing on two low-drag, long-range boat-tail bullets, so you can see how the G1 and G7 Ballistic coefficients compare:

G1 BCs, averaged between 1500 fps and 3000 fps:
Berger 180 VLD: 0.659 lb/in²
JLK 180: 0.645 lb/in²

The reason the BC for the JLK is less is mostly because the meplat was significantly larger on the particular lot that I tested (0.075″ vs 0.059″; see attached drawings).

For bullets like these, it’s much better to use the G7 standard. The following BCs are referenced to the G7 standard, and are constant for all speeds.

G7 BCs:
Berger 180 VLD: 0.337 lb/in²
JLK 180: 0.330 lb/in²

Many modern ballistics programs, including the free online JBM Ballistics Program, are able to use BCs referenced to G7 standards. When available, these BCs are more appropriate for long range bullets, according to Bryan.

[Editor’s NOTE: BCs are normally reported simply as an 0.XXX number. The lb/in² tag applies to all BCs, but is commonly left off for simplicity.]

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