Bryan Litz and The Science of Accuracy Academy have released a Podcast with vital information for all handloaders. This Podcast examines the effects of humidity variances on powder. Bryan notes: “If you want to know how much this can matter, we’re talking up to 200 fps difference for the same load of H4350 in 6.5 Creedmoor” at opposite extremes of humidity.
Bryan adds that “Most shooters don’t realize what a big deal this can be — it overshadows many of our efforts to make consistent velocity and hit targets. This can happen in loaded rounds not just for hand loading where you expose powder to ambient humidity. This is especially important for hunters considering the range of environments hunting ammo goes through.”
Subscriptions for Applied Ballistics The Science of Accuracy Academy Podcasts
If you like this podcast, and want to learn more from Brian Litz and his Applied Ballistics team, you can order a subscription to the Academy. Priced at $9.95/mo, this subscription will allow you to access all podcasts, exclusive videos, learning resources, and bullet data sheets.
If you are evaluating a firearm for self-defense use, you should consider three main factors: Reliability, Functionality (sights, trigger, ergonomics), and Effectiveness (ability to halt/neutralize threats). Regarding effectiveness, you need to consider what happens when the projectiles from your firearm reach the target. That involves penetration and terminal ballistics.
A 12ga shotgun is very effective inside 20 yards, with less risk of over-penetration* vs. a centerfire rifle.
You’ve probably heard the term “Terminal Ballistics”. But do you really know what this refers to? Fundamentally, “Terminal Ballistics” describes the behavior of a projectile as it strikes, enters, and penetrates a target. Terminal Ballistics, then, can be said to describe projectile behavior in a target including the transfer of kinetic energy. Contrast this with “External Ballistics” which, generally speaking, describes and predicts how projectiles travel in flight. One way to look at this is that External Ballistics covers bullet behavior before impact, while terminal ballistics covers bullet behavior after impact.
The study of Terminal Ballistics is important for hunters, because it can predict how pellets, bullets, and slugs can perform on game. This NRA Firearm Science video illustrates Terminal Ballistics basics, defining key terms such as Impact Crater, Temporary Cavity, and Primary Cavity.
External Ballistics, also called “exterior ballistics”, is the part of ballistics that deals with the behavior of a non-powered projectile in flight.
Terminal Ballistics, a sub-field of ballistics, is the study of the behavior and effects of a projectile when it hits its target.
*This Shooting Illustrated article discusses over-penetration risks with a variety of cartridge types. “A bullet passing through a threat and continuing with the potential to cause unintentional damage to a bystander or object is a situation commonly described as over-penetration.”
You can do your own experimental calculations using JBM Online Ballistics (free to use). Here is an extreme example, with two printouts (generated with Point Blank software), one showing bullet trajectory at sea level (0′ altitude) and one at 20,000 feet. For demonstration sake, we assigned a low 0.2 BC to the bullet, with a velocity of 3000 fps.
One of our readers asked “What effect does altitude have on the flight of a bullet?” The simplistic answer is that, at higher altitudes, the air is thinner (lower density), so there is less drag on the bullet. This means that the amount of bullet drop is less at any given flight distance from the muzzle. Since the force of gravity is essentially constant on the earth’s surface (for practical purposes), the bullet’s downward acceleration doesn’t change, but a bullet launched at a higher altitude is able to fly slightly farther (in the thinner air) for every increment of downward movement. Effectively, the bullet behaves as if it has a higher ballistic coefficient.
Forum member Milanuk explains that the key factor is not altitude, but rather air pressure. Milanuk writes:
“In basic terms, as your altitude increases, the density of the air the bullet must travel through decreases, thereby reducing the drag on the bullet. Generally, the higher the altitude, the less the bullet will drop. For example, I shoot at a couple ranges here in the Pacific Northwest. Both are at 1000′ ASL or less. I’ll need about 29-30 MOA to get from 100 yard to 1000 yards with a Berger 155gr VLD @ 2960fps. By contrast, in Raton, NM, located at 6600′ ASL, I’ll only need about 24-25 MOA to do the same. That’s a significant difference.
Note that it is the barometric pressure that really matters, not simply the nominal altitude. The barometric pressure will indicate the reduced pressure from a higher altitude, but it will also show you the pressure changes as a front moves in, etc. which can play havoc w/ your calculated come-ups. Most altimeters are simply barometers that read in feet instead of inches of mercury.”
As Milanuk states, it is NOT altitude per se, but the LOCAL barometric pressure (sometimes called “station pressure”) that is key. The two atmospheric conditions that most effect bullet flight are air temperature, and barometric pressure. Normally, humidity has a negligible effect.
It’s important to remember that the barometric pressure reported on the radio (or internet) may be stated as a sea level equivalency. So in Denver (at 6,000 feet amsl), if the local pressure is 24″, the radio will report the barometric pressure to be 30″. If you do high altitude shooting at long range, bring along a Kestrel, or remember to mentally correct the radio station’s pressure, by 1″ per 1,000 feet.”
Let’s say you’ve purchased a new scope, and the spec-sheet indicates it is calibrated for quarter-MOA clicks. One MOA is 1.047″ inches at 100 yards, so you figure that’s how far your point of impact (POI) will move with four clicks. Well, unfortunately, you may be wrong. You can’t necessarily rely on what the manufacturer says. Production tolerances being what they are, you should test your scope to determine how much movement it actually delivers with each click of the turret. It may move a quarter-MOA, or maybe a quarter-inch, or maybe something else entirely. (Likewise scopes advertised as having 1/8-MOA clicks may deliver more or less than 1 actual MOA for 8 clicks.)
Reader Lindy explains how to check your clicks: “First, make sure the rifle is not loaded. Take a 40″ or longer carpenter’s ruler, and put a very visible mark (such as the center of an orange Shoot’N’C dot), at 37.7 inches. (On mine, I placed two dots side by side every 5 inches, so I could quickly count the dots.) Mount the ruler vertically (zero at top) exactly 100 yards away, carefully measured.
Place the rifle in a good hold on sandbags or other rest. With your hundred-yard zero on the rifle, using max magnification, carefully aim your center crosshairs at the top of the ruler (zero end-point). Have an assistant crank on 36 (indicated) MOA (i.e. 144 clicks), being careful not to move the rifle. (You really do need a helper, it’s very difficult to keep the rifle motionless if you crank the knobs yourself.) With each click, the reticle will move a bit down toward the bottom of the ruler. Note where the center crosshairs rest when your helper is done clicking. If the scope is accurately calibrated, it should be right at that 37.7 inch mark. If not, record where 144 clicks puts you on the ruler, to figure out what your actual click value is. (Repeat this several times as necessary, to get a “rock-solid”, repeatable value.) You now know, for that scope, how much each click actually moves the reticle at 100 yards–and, of course, that will scale proportionally at longer distances. This optical method is better than shooting, because you don’t have the uncertainly associated with determining a group center.
Using this method, I discovered that my Leupold 6.5-20X50 M1 has click values that are calibrated in what I called ‘Shooter’s MOA’, rather than true MOA. That is to say, 4 clicks moved POI 1.000″, rather than 1.047″ (true MOA). That’s about a 5% error.
I’ve tested bunches of scopes, and lots have click values which are significantly off what the manufacturer has advertised. You can’t rely on printed specifications–each scope is different. Until you check your particular scope, you can’t be sure how much it really moves with each click.
I’ve found the true click value varies not only by manufacturer, but by model and individual unit. My Leupold 3.5-10 M3LR was dead on. So was my U.S.O. SN-3 with an H25 reticle, but other SN-3s have been off, and so is my Leupold 6.5-20X50M1. So, check ‘em all, is my policy.”
From the Expert: “…Very good and important article, especially from a ballistics point of view. If a ballistics program predicts 30 MOA of drop at 1000 yards for example, and you dial 30 MOA on your scope and hit high or low, it’s easy to begin questioning BCs, MVs, and everything else under the sun. In my experience, more than 50% of the time error in trajectory prediction at long range is actually scope adjustment error. For serious long range shooting, the test described in this article is a MUST!” — Bryan Litz, Applied Ballistics LLC.
Bryan also uses a Tall Target Test to determine true click values. CLICK HERE to read a detailed, explanatory article about Litz’s Tall Target Test.
This article, as published in AccurateShooter.com, contains copyrighted content. It shall not be republished in whole or in part without advanced permission in writing. The act of republishing constitutes legal consent to licensing fees.
Here’s a simple solution for lumpy front sandbags. Cut a small block the width of your fore-end and place that in the front bag between matches. You can tap it down firmly with a rubber mallet.
The block will keep the front bag nice and square, without bunching up in the center. That will help your rifle track straight and true. Rick Beginski uses wood (see photo), while our friend John Southwick uses a small block of metal. The metal block might work a little better, but the wood version is easier to make with simple tools. Shown above is a slick Delrin block with a built-in bubble level used with a quality J.J. Loh front rest. Using a good block on your front bag helps ensure that the actual top surface of your front bag is level, as distinct from the front rest assembly.
Jim Borden, the very knowledgeable owner of Borden Accuracy, provided an interesting historical insight about barrel fitting and the term “blueprinting”. Jim has posted on his Borden Accuracy Facebook page an explanation of the term “blueprinting” as it originally was used with respect to barrel/shoulder/lug fitting.
Barrel/Shoulder Fit and Blue-Printing
Jim told us: “Something often overlooked on barrel installation is the shoulder fit. Many are so overly obsessed with doing a crank-on fit of threads that the shoulder contact is overlooked. Full, solid barrel shoulder to recoil lug or action face is critical to optimum accuracy and precision.
Many years ago part of the ‘blueprinting’ of an action was the use of Prussian blue to ‘blueprint’ lug fit, thread fit, and barrel shoulder fit. It was a colloquial expression that had nothing to do referring to a blueprint or drawing of the action.” Bet you didn’t know that!
About the photo below, Jim noted: “the fuzzy look on the threads is a liberal coating of Never-Seez thread lubricant.”
Look carefully to see the Prussian Blue applied to the barrel shoulder, plus Never Seez on threads.
The USAMU has published a “how-to” article about bullet sorting. While many of us may sort bullets by base-to-ogive length (and/or weight), the USAMU story explores the “how and why” of sorting bullets by Overall Length (OAL). Read the article highlights below, and make your own decision as to whether OAL sorting is worth the time and effort. Bryan Litz of Applied Ballistics says that sorting by OAL is not a bad idea, but base-to-ogive bullet sorting probably represents a better investment of your time.
Bullet Sorting by Overall Length
We’d like to share a specialized handloading technique which we’ve long found beneficial to our long-range (600 yards and beyond) accuracy. Sorting of bullets for extreme long range (LR) accuracy is not difficult to do, but some background in theory is needed.
Here at USAMU’s Handloading Shop, we only sort individual bullets for the most demanding Long-Range applications and important competitions. Only the most accurate rifles and shooters can fully exploit the benefits of this technique. The basic sorting process involves measuring the Overall Length (OAL) of the bullets, and grouping them in 0.001″ increments. It’s not unusual to find lots of match bullets that vary as much as 0.015″-0.020″ in length throughout the lot, although lots with much less variation are seen as well. Even in bullet lots with 0.015″ OAL variation, the bullet base-to-ogive length will show much less variation. Hence, our basic sort is by bullet OAL. One obvious benefit of sorting is easily seen in the attached photo. The few bullets that are VERY different from the average are culled out, reducing probable fliers.
How does one know what OAL increments to use when sorting? The answer is simple. As each lot of bullets is unique in its OAL distribution, it’s best to sample your bullet lot and see how they are distributed. In the attached photo, you will see a set of loading trays with a strip of masking tape running along the bottom. Each vertical row of holes is numbered in 0.001″ increments corresponding to the bullets’ OAL. A digital caliper makes this task much easier. As each bullet is measured, it is placed in the line of holes for its’ OAL, and gradually, a roughly bell-shaped curve begins to form.
Note that near the center, bullets are much more plentiful than near the edges. At the extreme edges, there are a few that differ markedly from the average, and these make great chronograph or sighting-in fodder. We recommend using a sample of 200 bullets from your lot, and 300 is even better. Some bullet lots are very consistent, with a tall, narrow band of highly-uniform bullets clustered together over just a few thousandths spread. Other lots will show a long, relatively flat curve (less uniform), and you may also see curves with 2 or more “spikes” separated by several 0.001″ OAL increments.
Bullet Sorting — OAL vs. Base-to-Ogive vs. Weight
Expert advice from Bryan Litz, Applied Ballistics
I’m often asked what is a the best measure to sort bullets by, and the answer (to this and many other questions in ballistics) is: it depends.
Choosing to sort by overall length (OAL), base to ogive (BTO), bearing surface, weight, etc. can get overwhelming. Shooters typically look for something they can measure, which shows a variation and sort by that. It’s common for dimensional variations to correlate. For example, bullets which are longer in OAL are typically also shorter in BTO, and have longer noses. All these are symptoms of a bullet that was pushed a little further into the pointing die, or possibly had more than average lube while being swaged. So in essence, if you sort by BTO, you’re measuring one symptom which can indicate a pattern in the bullets shape.
So, the question still stands — what should you measure? You’ll always see more variation in OAL than BTO, so it’s easier to sort by OAL. But sometimes the bullet tips can be jagged and have small burrs which can be misleading. Measuring BTO will result in a lower spread, but is a more direct measure of bullet uniformity.
Then there’s the question of; how much variation is too much, or, how many bins should you sort into? Shooters who see 0.025” variation in BTO may choose to sort into 5 bins of 0.005”. But if you have only 0.005” variation in the box, you’ll still sort into 5 bins of 0.001”. What’s correct? You have to shoot to know. Live fire testing will answer more questions, and answer them more decisively than any amount of discussion on the subject. The test I recommend is to identify bullets on the extreme short end of the spectrum, and some on the extreme long end. Load at least 10 rounds of each, and take turns shooting 5-shot groups with them. If there is a difference, it will be evident. The results of the testing will answer your question of: should I sort based on X, Y, or Z?”
You can read more discussions on this and other similar subjects in our Accurateshooter.com Shooters’ Forum. Here’s a link to a thread discussing bullet sorting: Bullet Sorting Thread
Ask 10 shooters about barrel cleaning and you’ll get 10 different opinions. This reflects that fact that different fouling problems demand different solutions. For example, solvents that work well for copper may not be the best for hard carbon (and vice-versa). To come up with the right solution, first you must understand the nature of the fouling in your barrel.
John Krieger Interview with AccurateShooter at SHOT Show:
The debate about the proper care of a match barrel is a hot one, spiked with folklore and old wives’ tales, Lohman said. He and his staff set out to set the record straight: “We tried to interject some science into the discussion of cleaning a match barrel,” he explained. In his article, Lohman writes:
Why worry about a little barrel fouling when the throat is subjected to a brutal 5,600° F volcano at 55,000 PSI? To investigate these and other questions about taking care of a match barrel, we spoke with a dozen experts and share their knowledge in this first of a series of articles.
After listening to folks who shoot, build barrels or manufacture cleaning solvents for a living, we concluded that even the experts each have their own unique recommendations on how to care for a match barrel. But they all agree on one thing — the gun will tell you what it likes best. Because the life expectancy of a match barrel is about 1,500 to 2,500 rounds, the objectives of cleaning one should include: preserve accuracy, slow the erosion, and remove fouling — all without damaging the gun. This article doesn’t claim that one cleaning method is better than the next. Rather, we set out to interject a little science into the discussion and to share some lessons learned from experts in the field.
For more Shooting Sports USA articles, visit www.ssusa.org.
Here’s a tip we feature every year or so, because it is something that costs nothing, yet can be very useful in the reloading process. With a simple, easy modification to a fired case, you can determine the length to lands in your rifle barrel. As long as you set the tension right, the measurements should be repeatable, and you’ve just saved yourself $49.94 — the combined cost of a Hornady commercial OAL gauge ($43.95) and Modified Case ($5.99).
To achieve best accuracy with a rifle, you must control bullet seating depth very precisely, so all bullets end up in the same place relative to the entrance of the lands, every time. There may be multiple cartridge OALs which prove accurate. However, with each, you first need to determine a “zero” point — a reliable, and repeatable OAL where the bullet is “just touching” the lands.
There are tools, such as the Hornady (formerly Stoney Point) OAL Gauge, that will help you find a seating OAL just touching the lands. However, the tool requires that you use a special modified case for each cartridge you shoot. And, while we find that the Hornady OAL Gauge is repeatable, it does take some practice to get in right.
Make Your Own Length-to-Lands Gauge with a Dremel
Here’s an inexpensive alternative to the Hornady OAL tool — a slotted case. Forum member Andris Silins explains how to create a slotted case to measure length to the lands in your rifle:
“Here’s what I did to find length to lands for seating my bullets. I made four cuts into the neck of fire-formed brass. Then I pressed the bullet in lightly and chambered the entire gauge. As the cartridge chambers, the bullet slides back into the case to give you length to lands. It took less than five minutes to get it cut and working. A little light oil in the barrel just past the chamber helps ensure the bullet does not get stuck in the lands. It works great and is very accurate.
How to Adjust Tension — Length and Number of Neck Cuts
I made the cuts using a Dremel with a cut-off wheel. You can adjust tension two ways. First, you can make the cuts longer or shorter. Longer cuts = less tension. If you used only three cuts instead of four you would get more tension. The trick is to be gentle when you open and close the bolt. If you ram the bolt closed you may wedge the bullet into the lands. When you open the bolt it helps to keep a finger or two near by to guide the case out straight because the ejector wants to push it sideways.”
We have used NO-LEAD Cleaner in rimfire benchrest rifles similar to this modified Suhl 150-1. It helped restore accuracy with minimal brushing.
Made by the same smart folks that created Wipe-Out™, and Carb-Out™, NO-LEAD Brushless Lead Remover™ really works. Honest. If you are an active rimfire shooter, or if you shoot cast lead-alloy bullets in centerfire rifles and pistols, you should try this product. We now use NO-LEAD in our rimfire benchrest rifles, and in some centerfire guns that receive a steady diet of soft-alloy cast bullets (90%+ lead). (With rimfire guns, you don’t need to use NO-LEAD very often — maybe every 300-400 rounds unless you have a real fouler of a barrel.)
If you’ve got stubborn lead fouling in a rimfire barrel, or on a pistol’s muzzle brake/compensator, you should definitely give this stuff a try. We don’t know how but it does soften lead deposits. The manufacturer says you don’t need brushes, but we found that a bit of brushing (after NO-LEAD application) can help remove more serious lead build-up.
Yes we were surprised to find a lead remover that really works. We tried a half-dozen other lead “cleaners” that promised to dissolve lead and most of them, we discovered, are nearly useless. There’s a reason for that, as the lead alloys used in bullets don’t react to typical petrochemical-based solvents. It took the Wipe-Out chemists over five years to perfect this water-based solution that really does dissolve lead.
NO-LEAD Cleaning Procedure — Read Carefully NO-LEAD Lead Remover is a clear, red gel that is easy to apply. Just swab it in your bore (or on muzzle brakes) with wet patches or bore mop and let it sit for a few minutes. (The manufacturer says you can leave the NO-LEAD for up to 20 minutes, but that long of a dwell time does not seem necessary with our rimfire barrels.) When it contacts lead it will start to foam and you’ll see that the NO-LEAD solvent turns a pastel pink when it dissolves lead. The pink comes from the formation of lead oxide. After the recommended dwell time, simply patch out the dissolved lead deposits (you can also use a nylon brush for stubborn lead build-up).
NOTE: After cleaning, it is very important that you get all the NO-LEAD out of your barrel, and neutralize it. We recommend following the application of NO-Lead with Wipe-out or Patch-Out to neutralize the NO-LEAD, clear the bore, and remove residual carbon and copper fouling. If you don’t have Wipe-Out or Patch-out, flush the barrel thoroughly with Rubbing Alcohol or even a solution of Dawn dish detergent — then re-oil the bore.
Be Sure to Neutralize NO-LEAD After Use
Remember that N0-LEAD is a strong, slightly acidic chemical that needs to be neutralized after use. If you leave it on a nice, blued barrel for too long, it can harm the bluing. NO-LEAD will remove all the surface oils from the barrel bore. For this reason it is recommended that you neutralize NO-LEAD with Wipe-Out, or Patch-Out, which both contain effective corrosion inhibitors. If you don’t have those products, once you’ve flushed the NO-LEAD with something like rubbing alcohol, then follow with a gun oil. Caution: A petroleum-based gun oil will NOT, by itself, neutralize NO-LEAD. You need to neutralize first, then apply the corrosion inhibitor (or do it all in one step with Wipe-Out or Patch-Out).
Where to Buy NO-LEAD Lead Remover
NO-LEAD Lead Remover costs $18.55 for an 8 oz. squeeze bottle with a flip-top spout. This product is sold directly by Sharp Shoot-R Precision Products through Sharpshootr.com, or you can purchase NO-LEAD through many other online vendors. For more information, send an email via the Sharp Shoot-R Contact Form or or contact SharpShoot-R at (785) 883-4444. You can ask for Terry Paul, Sharp Shoot-R’s owner and the master chemist who developed the NO-LEAD formula.
One of our readers asked “What effect does altitude have on the flight of a bullet?” The simplistic answer is that, at higher altitudes, the air is thinner (lower density), so there is less drag on the bullet. This means that the amount of bullet drop is less at any given flight distance from the muzzle. Since the force of gravity is essentially constant on the earth’s surface (for practical purposes), the bullet’s downward acceleration doesn’t change, but a bullet launched at a higher altitude is able to fly slightly farther (in the thinner air) for every increment of downward movement. Effectively, the bullet behaves as if it has a higher ballistic coefficient.
Reader Lindy explains how to check your clicks: “First, make sure the rifle is not loaded. Take a 40″ or longer carpenter’s ruler, and put a very visible mark (such as the center of an orange Shoot’N’C dot), at 37.7 inches. (On mine, I placed two dots side by side every 5 inches, so I could quickly count the dots.) Mount the ruler vertically (zero at top) exactly 100 yards away, carefully measured.
Here’s a simple solution for lumpy front sandbags. Cut a small block the width of your fore-end and place that in the front bag between matches. You can tap it down firmly with a rubber mallet.
Barrel/Shoulder Fit and Blue-Printing
Made by the same smart folks that created Wipe-Out™, and Carb-Out™, 
Where to Buy NO-LEAD Lead Remover
