November 20th, 2013
In discussions of ballistics, you’ll see references to “tangent” and “secant” bullet shapes. We know that, for many readers, these terms can be confusing. To add to the confusion, bullet makers don’t always identify their projectiles as secant or tangent designs. This article provides a basic explanation of tangent and secant designs, to help you understand the characteristics of both bullet shapes.
Tangent vs. Secant vs. Hybrid
Most match bullets produced today use a tangent ogive profile, but the modern VLD-style bullets employ a secant profile. To further complicate matters, the latest generation of “Hybrid” projectiles from Berger Bullets feature a blended secant + tangent profile to combine the best qualities of both nose shapes. The secant section provides reduced drag, while the tangent section makes the bullet easier to tune, i.e. less sensitive to bullet seating depth position.
Berger Bullets ballistician Bryan Litz explains tangent and secant bullet ogive designs in a glossary section of his Applied Ballistics website, which we reprint below. Bryan then explains how tangent and secant profiles can be combined in a “hybrid” design.
How Bullet Ogive Curves are Defined
While the term “ogive” is often used to describe the particular point on the bullet where the curve reaches full bullet diameter, in fact the “ogive” properly refers to the entire curve of the bullet from the tip to the full-diameter straight section — the shank. Understanding then, that the ogive is a curve, how is that curve described?
LITZ: The ogive of a bullet is usually characterized by the length of its radius. This radius is often given in calibers instead of inches. For example, an 8 ogive 6mm bullet has an ogive that is a segment of a circular arc with a radius of 8*.243 = 1.952”. A .30-caliber bullet with an 8 ogive will be proportionally the same as the 8 ogive 6mm bullet, but the actual radius will be 2.464” for the .30 caliber bullet.
For a given nose length, if an ogive is perfectly tangent, it will have a very specific radius. Any radius longer than that will cause the ogive to be secant. Secant ogives can range from very mild (short radius) to very aggressive (long radius). The drag of a secant ogive is minimized when its radius is twice as long as a tangent ogive radius. In other words, if a tangent ogive has an 8 caliber radius, then the longest practical secant ogive radius is 16 calibers long for a given nose length.”
Ogive Metrics and Rt/R Ratio
LITZ: There is a number that’s used to quantify how secant an ogive is. The metric is known as the Rt/R ratio and it’s the ratio of the tangent ogive radius to the actual ogive radius for a given bullet. In the above example, the 16 caliber ogive would have an Rt/R ratio of 0.5. The number 0.5 is therefore the lowest practical value for the Rt/R ratio, and represents the minimum drag ogive for a given length. An ogive that’s perfectly tangent will have an Rt/R ratio of 1.0. Most ogives are in between an Rt/R of 1.0 and 0.5. The dimensioned drawings at the end of my Applied Ballistics book provide the bullets ogive radius in calibers, as well as the Rt/R ratio. In short, the Rt/R ratio is simply a measure of how secant an ogive is. 1.0 is not secant at all, 0.5 is as secant as it gets.
Hybrid Bullet Design — Best of Both Worlds?
Bryan Litz has developed a number of modern “Hybrid” design bullets for Berger. The objective of Bryan’s design work has been to achieve a very low drag design that is also “not finicky”. Normal (non-hybrid) secant designs, such as the Berger 105gr VLD, deliver very impressive BC values, but the bullets can be sensitive to seating depth. Montana’s Tom Mousel has set world records with the Berger 105gr VLD in his 6mm Dasher, but he tells us “seating depth is critical to the best accuracy”. Tom says a mere .003″ seating depth change “makes a difference”. In an effort to produce more forgiving high-BC bullets, Bryan Litz developed the hybrid tangent/secant bullet shape.
Bryan Litz Explains Hybrid Design and Optimal Hybrid Seating Depths
Story sourced by Edlongrange.
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November 4th, 2013
Ten bucks off an order of $25.00 or more? Now that’s a deal. Applied Ballistics LLC is making this limited-time one-week special offer as a way of thanking its Facebook followers. Bryan Litz explains: “To show our appreciation and celebrate reaching 2,500 likes, we are offering everyone $10 off your entire purchase of $25 or more. This offer is good today (November 4, 2013) through Sunday, November 10, 2013.” To get your onetime discount, simply enter offer Code ‘FBLike’ when shopping via the Applied Ballistics Webstore. NOTE: You do NOT need to be registered with Facebook to qualify for the ten-dollar discount. This deal is for everybody. Can’t complain about that.
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October 24th, 2013
The Applied Ballistics Kestrel 4500 Shooters’ Weather Meter has a new software upgrade available. You will find instructions for connecting and upgrading your Kestrel 4500 at this link:
CLICK HERE for Applied Ballistics
Kestrel Software Upgrade.
Read Comments on Sniper’s Hide Forum
Also, there is a thread on the Snipers Hide Forum in which Applied Ballistics and Kestrel Pro Staff are responding to questions/issues related to use of the Applied Ballistics Kestrels.
Bryan Litz of Applied Ballistics LLC wants to express appreciation for Kestrel users who have posted input: “Thanks to the users who provided valuable feedback that was used to make the product better.”
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October 16th, 2013
As you may know already, Bryan Litz of Applied Ballistics LLC has produced an excellent 3-Disc DVD set entitled Putting Rounds on Target. When one views the end result one can forget the hard work and tribulations that go into making such a production. Sometimes Mother Nature doesn’t cooperate when the crew is out at the range.
Bryan tells us:
“Filming for ‘Putting Rounds on Target’ proved to be a bit more challenging then we had expected. For this segment in the third disk, we packed up and set up everything over half a dozen times to keep the camera and shooting equipment dry as the sun played Peek-a-boo behind rain clouds. The chilled temperatures, required a lot of hot coffee, but the lack of restrooms made for a long day. In the end, it was totally worth it!
Watch Trailer Video of Putting Rounds on Target DVD Set
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October 14th, 2013
Gear Review by German Salazar
This article originally appeared in German Salazar’s Rifleman’s Journal website.
Many of you have doubtlessly read Bryan Litz’s articles in Precision Shooting and on his Applied Ballistics website about various current long-range bullets. Bryan’s work carries a great deal of weight in the world of ballistics, so his comments (and mathematical proofs) regarding the benefits of bullet pointing certainly caught my attention. Bullet pointing, like meplat trimming, is an effort to reduce the ballistic inconsistency created by the somewhat jagged tip of the jacket where the bullet forming dies bring it to a point in the manufacturing process. Of course, we could eliminate this problem altogether by shooting closed-tip, open-base bullets like the Lapua D46, but that merely shifts the jacket problem to the other end of the bullet.
In any event, hollow point bullets rule the accuracy world today, so John Whidden, multi-time National Long Range Champion at Camp Perry and a talented gunsmith and designer to boot, came up with a very handy tool to let us make those hollow points pointier. Let’s have a look at John’s tool and see how it works.
The Whidden Bullet Pointing Die System uses a Forster bullet seating die body as its basic structure and that’s a good choice given the quality machining Forster does on these. The real heart of the tool comes in two parts: the caliber sleeve and the pointing die that fits inside the sleeve. In fact, to point up different caliber bullets, you only need to change the caliber sleeve, everything else remains the same. The last item is the bullet base that slips into a standard .308 shellholder and supports the bullet as it goes into the die body.
It took me less than five minutes to get everything set up, including changing the caliber sleeve from 6mm to .30 caliber. John’s instruction sheets are well illustrated and clearly written; you should have no problem getting up and running.
Pointing the bullets is as easy as sizing a piece of brass. You can see in the top photo the difference between a few pointed bullets and a few un-pointed ones. The innermost pointed bullet in the picture was my first attempt and I adjusted the die a little after that, you can see that the others are closed a little more. John even includes a couple of sample bullets so that you can see one done right and one done wrong. That is a nice addition that can help you achieve the desired results.
I think Bryan’s work supports the validity of this concept and John’s tool puts it into practice in a simple-to-use manner that makes it just about impossible to do any damage to the bullet. I have shot pointed bullets in various calibers at many matches now. Pointing is not a “miracle cure”, but I believe that pointing bullet tips can produce long-range accuracy gains, through reduced vertical dispersion, for many popular types of match bullets. The Whidden Bullet Pointing Die System retails for $210.00 (with one insert). Additional die inserts are $40.00 each. Extra caliber sleeves are also $40.00. You can purchase directly from Whidden Gunworks, or from Sinclair International.
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August 7th, 2013
We want to say “Happy Birthday” to Bryan Litz of Applied Ballistics LLC. Bryan came to earth from Planet Krypton on August 7, 1979, making him a ripe old 34 years of age today. (One more year and he’s over the hill).
In an industry where many products are conceived and marketed by folks who spend more time on the golf course than the shooting range, it’s reassuring to know that there are still guys like Bryan who shoot what they sell, and who put in the trigger-time to acquire (and maintain) world-class shooting skills. Bryan, who actually worked as a rocket scientist before founding Applied Ballistics, is one of the nation’s leading long-range sling shooters — with the trophies to prove it. As well, the bullets Bryan designed for Berger bullets, particularly the Berger Hybrids, are helping competitive shooters around the world shoot higher scores and win more matches.
Palma Match from a Shooter’s Perspective
For those of you who haven’t seen it before, here is a “shooter’s POV” video of Bryan shooting an 800-yard Palma match. In the video Bryan shoots a 149-12X over a 15-shot string. NOTE: This video was speeded up in editing to keep it to a reasonable length.
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July 26th, 2013
Kestrel 4500 Shooter’s Weather Meters with integrated Applied Ballistics software are finally shipping. Bryan Litz, founder of Applied Ballistics LLC, reports: “Long range shooting just got a little easier. We are pleased to announce that the Applied Ballistics Kestrels have arrived! They are now available for immediate shipment. Pre-orders will ship today.” To order, follow this link for the Applied Ballistics Store.
These Kestrel 4500 Shooter’s Weather Meters include a full-featured ballistics solver and databases of bullets so you can accurately plot trajectories. The Applied Ballistics software accesses the environmental data (wind speed, humidity, altitude etc.) recorded by the Kestrel to provide a more precise trajectory.
Features of Kestrel 4500 with Applied Ballistics Software
With integrated Applied Ballistics software, Kestrel users are now able to select from either G1 or G7 ballistic coefficients (BC) when calculating a trajectory. The new Kestrel 4500 Shooter’s Weather Meter also offers the very extensive “Litz”-measured BC library of over 225 bullets. In addition to these features, users can “train” the software to match a specific rifle based on observed impacts at long range with the ballistics calibration feature. With more accurate BC data, shooters are empowered to make more precise trajectory calculations. The new Kestrel Shooter’s Weather Meter can also receive data from wind sensor arrays designed and sold by Applied Ballistics. Like all Kestrels, the Shooter’s Weather Meter is IP67 waterproof and ruggedized to MIL-STD-810F standards.
Every Kestrel meter is pocket-sized, rugged, accurate, waterproof, easy-to-use, and backed by an industry-leading, five-year warranty.
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July 23rd, 2013
On the Applied Ballistics Facebook page, Ballistician Bryan Litz regularly offers a “Tuesday Trivia” question about ballistics. Today’s brain-teaser is a true/false question about bullet stabilization. On shooting forums you often find heated arguments about “over-stabilization”. Bryan wants readers to consider the issue of over-stabilization and answer a challenge question…
Is This Statement TRUE or FALSE?
“The problem with ‘over-stabilizing’ a bullet (by shooting it from an excessively fast twist rate) is that the bullet will fly ‘nose high’ on a long range shot. The nose-high orientation induces extra drag and reduces the effective BC of the bullet.”
True or False, and WHY?
Click the “Post Comment” link below to post your reply (and explain your reasoning).
Diagram from the University of Utah Health Sciences Library Firearm Ballistics Tutorial
Bullet Movement in Flight — More Complicated Than You May Think
Bullets do not follow a laser beam-like, perfectly straight line to the target, nor does the nose of the bullet always point exactly at the point of aim. Multiple forces are in effect that may cause the bullet to yaw (rotate side to side around its axis), tilt nose-up (pitch), or precess (like a spinning top) in flight. These effects (in exaggerated form) are shown below:
Yaw refers to movement of the nose of the bullet away from the line of flight. Precession is a change in the orientation of the rotational axis of a rotating body. It can be defined as a change in direction of the rotation axis in which the second Euler angle (nutation) is constant. In physics, there are two types of precession: torque-free and torque-induced. Nutation refers to small circular movement at the bullet tip.
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July 15th, 2013
Bryan Litz, author of two leading books on practical rifle ballistics, has produced a 3-disc multi-media DVD: Putting Rounds on Target. We’ve previewed this new DVD set from Applied Ballistics. The DVDs are very thorough and very well-made. This is an important product release — there is nothing like it on the market. If you are a serious long-range shooter, put this DVD set on your wish list. Even if you own one or both of Bryan’s books, we know you can benefit from this product. The DVD format provides many graphic aids and video clips that illustrate key principles being covered. The three DVDs deliver as much information as a weekend shooting seminar… at a fraction of the cost.
The 3-disc DVD set costs just $39.95. That’s a bargain. Many shooting-related DVDs, with much less information, cost as much (or more) for a single disc. Putting Rounds on Target includes THREE discs, with a total run-time of 3 hours and 37 minutes. Plus, in addition, Bryan is tossing in a fourth, BONUS disc with 40 minutes of match coverage from the Berger SW Nationals. This documentary-style DVD highlights individual and team competition in Sling, F-Open and F-TR classes.
Watch Video Preview of Applied Ballistics 3-DVD Set
Interested? Pre-orders for Applied Ballistics’ new 3-disc instructional DVD set are now being accepted on the Applied Ballistics website for an expected ship date of August 15, 2013. CLICK HERE to Pre-Order.
Bryan tell us that his new DVD set was designed to give shooters the technical knowledge that will improve their scores on the target: “We explain the science involved in putting rounds on target at long range. After a classroom-type presentation (on video), we demonstrate the principles in live fire at the range with three different rifles (.308 Win, .284 Win, and .338 LM). In the end, DVD viewers will have the information and techniques required to master this technical subject matter. Follow along as the science is applied on the range to hit targets from 100 yards to a mile (1760 yards) with different rifles and ballistic solutions.”
Accuracy & Precision
Tall Target Test
Chronographs & Statistics
Run Time: 1 hour, 4 min
Primary Elevation Influences Wind
Using Ballistics Solvers
Short & Long Range Equipment
Run Time: 1 hour, 11 min
On The Range: .308 Win
On The Range: .284 Win
On The Range: .338 LM
Extended Range Shooting
Equipment for Extended Range Shooting
One Mile Shooting
Run Time: 1 hour, 22 min
FREE BONUS DISC
The Applied Ballistics instructional DVD set also includes a fourth BONUS disc: Long Range Competition: It’s Worth It. Filmed at the 2013 Berger SW Long Range Nationals, this 40-minute video DVD shows NRA long-range target shooting in Sling, F-TR, and F-Open divisions. Both individual and team competition are featured. If you like competitive shooting, you’ll enjoy this bonus disc.
About Bryan Litz
Champion shooter and Ballistician Bryan Litz explains and demonstrates the science of external ballistics for use in long range shooting. Bryan Litz is a well-known expert in the field of external ballistics. His books, Applied Ballistics for Long Range Shooting and Accuracy and Precision for Long Range Shooting are considered “required reading” for serious long range shooters — both recreational and professional.
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July 14th, 2013
Effects Of Cartridge Over All Length (COAL) And Cartridge Base To Ogive (CBTO) – Part 2
by Bryan Litz for Berger Bullets.
Part One of this series focused on the importance of COAL in terms of SAAMI standards, magazine lengths, seating depths, and pressure levels. Another measure of length for loaded ammunition is highly important to precision, namely Cartridge Base to Bullet Ogive Length (CBTO).
Figure 2. Chamber throat geometry showing the bullet jump to the rifling or lands.
Look at Figure 2. Suppose the bullet was seated out of the case to the point where the base of the bullet’s nose (ogive) just contacted the beginning of the riflings (the lands) when the bolt was closed. This bullet seating configuration is referred to as touching the lands, or touching the riflings and is a very important measurement to understand for precision hand-loading. Due to the complex dynamics of internal ballistics which happen in the blink of an eye, the distance a bullet moves out of the case before it engages the riflings is highly critical to precision potential. Therefore, in order to systematically optimize the precision of his handloads, it’s critically important that the precision hand-loader understands how to alter bullet seating depth in relation to the barrel rifling. Part of the required knowledge is understanding how to accurately and repeatably measure the Cartridge Base To Ogive (CBTO) dimension. This is explained in the FULL ARTICLE.
Bryan Litz offers an extended discussion on how to measure CBTO using different tools and methods, including the Hornady OAL gauge. You can read this discussion in the full article found on the Berger Bullets website. CLICK HERE to Read Full Article.
Why Not Use CBTO as a SAAMI Standard?
If CBTO is so important to rifle accuracy, you might ask, “Why is it not listed as the SAAMI spec standard in addition to COAL?” There is one primary reason why it is not listed in the standard. This is the lack of uniformity in bullet nose shapes and measuring devices used to determine CBTO.
Figure 4. Two different bullet shapes, seated to the same CBTO length, but different COAL. Note the shiny scratches on the bullets made by the comparator tool which indicates a point on the bullet ogive near where the ogive will engage the riflings.
Benefits of Having a Uniform CBTO
There is another aspect to knowing your CBTO when checking your COAL as it pertains to performance. With good bullets, tooling, and carefully-prepared cases you can easily achieve a CBTO that varies less than +/- .001″ but your COAL can vary as much as .025″ extreme spread (or more with other brands). This is not necessarily bad and it is much better than the other way around. If you have a CBTO dimension that varies but your COAL dimension is tight (within +/- .002″) then it is most likely that your bullet is bottoming out inside the seater cone on the bullet tip. This is very bad and is to be avoided. It is normal for bullets to have precisely the same nose shape and it is also normal for these same bullets to have nose lengths that can vary as much as .025″.
Article sourced by EdLongrange. We welcome tips from readers.
Summary of Cartridge Base To Ogive (CBTO) Discussion
Here are four important considerations regarding bullet seating depth as it relates to CBTO:
1. CBTO is a critical measurement to understand for handloaders because it’s directly related to precision potential, and you control it by simply setting bullet seating depth.
2. Tools and methods for measuring CBTO vary. Most of the measurement techniques have pitfalls (which may give rise to inconsistent results) that you should understand before starting out.
3. A CBTO that produces the best precision in your rifle may not produce the best precision in someone else’s rifle. Even if you have the same rifle, same bullets, same model of comparator gauges, etc. It’s possible that the gauges are not actually the same, and measurements from one don’t translate to the same dimension for another.
4. Once you find the CBTO that produces the best precision in your rifle, it’s important to allow minimal variation in that dimension when producing quality handloads. This is achieved by using quality bullets, tooling, and properly preparing case mouths and necks for consistent seating.
CLICK HERE to Read Full Article with More Info
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June 8th, 2013
The 2013 Remington-Bushmaster Long Range Regional was a smashing success at the Reade Range (Fallen Timber, Pennsylvania) last weekend. Some 98 competitors filled out four relays on the 25-target range.
This match has grown into a premier shooting event at one of the finest rifle range in the East. Paticipants shared $7000.00 worth of door prizes. In addition, nine Remington firearms (along with $5000 in cash prizes) were awarded to winning shooters and teams.
Everything went smoothly thanks to the dedicated involvement of so many people including Jennifer Litz, Amanda Litz, and Michelle Gallagher. Jennifer has been helping Michelle run the Berger Southwest Nationals for the last several years, so this year Michelle returned the favor by traveling to Pennsylvania to assist with Jennifer’s match.
The Friday morning practice session was well-attended, as was the team match. The range heated up to 90+ degrees Friday afternoon, but there were still fourteen, 4-shooter squads that stayed to compete in the afternoon including three full F-TR teams from Michigan.
$7000 Worth of Door Prizes Handed Out
Saturday opened with a greeting from Remington representative Ken Roxburgh and Range officer Tom Ferarro. Shooting commenced, and at the end of Day 1, the leaders had made themselves known. After the day’s shooting, food was served by the range. Following the meal, Applied Ballistics presented the door prizes. There were over $7000.00 worth of prizes. That means that every one of the 98 competitors took home an item from the prize table.
Sunday began with a sprinkle of rain in the morning. Bill Litz hit the F-TR class hard Sunday morning with an impressive 198-8X, which he followed up in the second match with a 194-6X to take the lead. In F-Open, Tom Delovich, Jim Murphy, and Tony Robertson all had strong starts and it was anyones match. In the Sling class, North Carolina all star Kent Reeve shot his Palma rifle in the masterful way that he does to the tune of 599-31Xs which won the day shooting against any rifles on the any-sight day. This was tremendous shooting by one of the worlds best.
Remington Provides Nine Long Guns to Top Shooters
Dinner was served as final results were being compiled and then final performance-based awards presented. In all, Remington awarded nine (9) firearms to the winners, who also received medals, and over $5,000 in cash winnings.
Organizer Bryan Litz states: “Based on this year’s attendance and success, the event is likely going to fill up next year and will be limited to 100 competitors. Remember to get your registration in early.”
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May 19th, 2013
Effects Of Cartridge Over All Length (COAL) And Cartridge Base To Ogive (CBTO) – Part 1
by Bryan Litz for Berger Bullets.
Many shooters are not aware of the dramatic effects that bullet seating depth can have on the pressure and velocity generated by a rifle cartridge. Cartridge Overall Length (COAL) is also a variable that can be used to fine-tune accuracy. It’s also an important consideration for rifles that need to feed rounds through a magazine. In this article, we’ll explore the various effects of COAL, and what choices a shooter can make to maximize the effectiveness of their hand loads.
Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI)
Most loading manuals (including the Berger Manual), present loading data according to SAAMI (Sporting Arms and Ammunition Manufacturers’ Institute) standards. SAAMI provides max pressure, COAL and many other specifications for commercial cartridges so that rifle makers, ammo makers, and hand loaders can standardize their products so they all work together. As we’ll see later in this article, these SAAMI standards are in many cases outdated and can dramatically restrict the performance potential of a cartridge.
Bullet seating depth is an important variable in the accuracy equation. In many cases, the SAAMI specified COAL is shorter than what a hand loader wants to load their rounds to for accuracy purposes. In the case where a hand loader seats the bullets longer than SAAMI specified COAL, there are some internal ballistic effects that take place which are important to understand.
Effects of Seating Depth / COAL on Pressure and Velocity
The primary effect of loading a cartridge long is that it leaves more internal volume inside the cartridge. This extra internal volume has a well known effect; for a given powder charge, there will be less pressure and less velocity produced because of the extra empty space. Another way to look at this is you have to use more powder to achieve the same pressure and velocity when the bullet is seated out long. In fact, the extra powder you can add to a cartridge with the bullet seated long will allow you to achieve greater velocity at the same pressure than a cartridge with a bullet seated short.
Figure 1. When the bullet is seated farther out of the case, there is more volume available for powder. This enables the cartridge to generate higher muzzle velocity with the same pressure.
When you think about it, it makes good sense. After all, when you seat the bullet out longer and leave more internal case volume for powder, you’re effectively making the cartridge into a bigger cartridge by increasing the size of the combustion chamber. Figure 1 illustrates the extra volume that’s available for powder when the bullet is seated out long.
Before concluding that it’s a good idea to start seating your bullets longer than SAAMI spec length, there are a few things to consider.
Geometry of a Chamber Throat
The chamber in a rifle will have a certain throat length which will dictate how long a bullet can be loaded. The throat is the forward portion of the chamber that has no rifling. The portion of the bullet’s bearing surface that projects out of the case occupies the throat (see Figure 2).
The length of the throat determines how much of the bullet can stick out of the case. When a cartridge is chambered and the bullet encounters the beginning of the rifling, known as the lands, it’s met with hard resistance. This COAL marks the maximum length that a bullet can be seated. When a bullet is seated out to contact the lands, its initial forward motion during ignition is immediately resisted by an engraving force.
Seating a bullet against the lands causes pressures to be elevated noticeably higher than if the bullet were seated just a few thousandths of an inch off the lands.
A very common practice in precision reloading is to establish the COAL for a bullet that’s seated to touch the lands. This is a reference length that the hand loader works from when searching for the optimal seating depth for precision. Many times, the best seating depth is with the bullet touching or very near the lands. However, in some rifles, the best seating depth might be 0.100″ or more off the lands. This is simply a variable the hand loader uses to tune the precision of a rifle.
CLICK HERE to Read Full Article with More Info
Article sourced by EdLongrange. We welcome tips from readers.
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