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August 4th, 2021

Bullet Geometry Basics: Tangent, Secant, and Hybrid Ogives

secant tangent hybrid ogive Bryan Litz Applied ballistics 200X Berger Hybrid bullet, .308 30 Caliber

In discussions of ballistics, you’ll see references to “tangent”, “secant”, and “hybrid” 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, secant, and hybrid ogive bullet designs, to help you understand the characteristics of these three basic 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.

hybrid bullet

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.”

Bryan Litz Explains Hybrid Design and Optimal Hybrid Seating Depths

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.

Berger Hybrid bullet, .308 30 CaliberHybrid 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.

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August 4th, 2021

Gun Digest 2022 76th Ed. Coming Soon — 592 Page Resource

Gun Digest 2022 76th Annual 592-page Gun book

The Gun Digest 2022, 76th Edition, can be pre-ordered now for $34.99 (paperback). Set for release on 8/17/2021, this 592-page resource covers rifles, shotguns, handguns, muzzleloaders, airguns, optics and more. We like the print edition, but there is also a PDF eBook version for $32.99 at Gundigeststore.com. You can read the PDF version on your tablet or computer. Both paperback and PDF versions provide hundreds of photos plus new product roundups, in-depth product tests, and scores of articles and stories.

The Gun Digest 2022 Annual is also available on Amazon.com. The paperback print edition is $31.87 at Amazon while the electronic Kindle version is $23.16 at Amazon.

Gun Digest 2022 Editor-in-Chief Phil Massaro has assembled a large team of respected industry authors for the new book, including Craig Boddington, Joe Coogan, Ron Spomer, Patrick Sweeney, Jim Supica, Thomas Gomez, Tom Turpin, Wayne van Zwoll, Bob Campbell and many more.

Gun Digest 2022 covers hunting, personal defense, target shooting, gunsmithing, and collecting. Historical articles look at the role played by firearms in our country. There are Updated Ballistics Tables, and the catalog section shows off the newest offerings in rifles, handguns, shotguns, muzzleloaders and air rifles.

Gun Digest 2022 76th Annual 592-page Gun book

Reports from the Field cover the newest firearms and accessories. A Testfire section brings readers up to date on product performance. And the annual photo essay spotlights the finest custom and engraved guns.

76th edition 2022 Gun digest book 592 pages amazon

Other Good Books from Gun Digest Media
Gun Digest Media produces numerous other quality books for rifle, pistol, and shotgun owners. Here are four volumes we recommend. These are offered in both paperback and eBook versions:

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August 4th, 2021

Kirsten Joy Weiss — Annie Oakley for the 21st Century

Kirsten Weiss trick shot Annie Oakley NRA All access

Talented sharpshooter Kirsten Joy Weiss is featured in an episode of NRA All Access. The show covers Kirsten’s development as a competitive shooter, and her success as a trick-shot artist with her own popular YouTube channel. Here’s the All Access segment featuring many of Kirsten’s most famous trick shots.

During the video Kirsten also talks about her background in shooting and how she wants to be a good ambassador for the shooting sports, “spreading the positive reality of shooting”. Kirsten explains: “The fun challenge and joy of shooting is important to me because I really wanted to be a positive example. So when the media says the ‘guns are a bad thing and nobody does anything good with guns’, they can say ‘Well, what about her [Kirsten]’?”

Kirsten: “I think that it’s important for young girls to have somebody that they can look up to… I feel responsibility to show young shooters coming up, especially females, that you can respect yourself and shoot a gun as well.”

annie oakley kirsten joy weiss trick shot YouTube channel

Kirsten Joy WeissA gifted “natural” shooter, Kirsten started shooting fairly late — at age 16. Despite her relatively late start, she learned very quickly, and managed to earn a place on the University of Nebraska shooting team. That literally opened up a new world for Kirsten: “During the course of my career, I’ve had a lot of success. I’ve gone to World Cups… in Zagreb, Croatia, in Munich, Germany. I’ve won National Championships, and got on to the U.S. Olympic short list, so it’s been a good career.”

Kirsten tells us: “A lot of people don’t think of shooting as a sport, but it absolutely is, and I would even go so far as to say that it is an art form.” We don’t know if this is art, sport, or magic, but very few shooters have the skill or flexibility to make this upside-down shot…

Kirsten Weiss trick shot Annie Oakley NRA All access

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