Close-up view of a sectioned case. This one here was “fixin’ to pop”, observed Glen Zediker.
Here are highlights from an article Glen Zediker wrote for the Midsouth Blog. In that article Glen, who sadly passed away in 2020, focused on cartridge brass. Glen identified the most common failures that appear with brass that has been shot multiple times, or which has been fired at excessive pressures. Glen explained some simple ways to check your cartridge brass to detect “early warning signs” of case failure, particularly case head separation, which can be very dangerous.
How Cases Degrade with Multiple Firings By Glen Zediker
This article explains when, and then how, to check after the progress of changes commencing with the firing on a new case. It’s the “progress of degeneration,” in a way of looking at it because the concern is getting a handle on when enough change in the brass has come about to require attention. Or abandonment. As said then, for me that’s 4 firings. That, as said last time, is when I might see changes that need attention. Also as said, that figure didn’t come out of a hat, but from my own notes in running my competition NRA High Power Rifle loads. [Editor’s Note: With Lapua brass, using moderate loads, in bolt-action rifles, we typically get about 10 good (match-worthy) firings. But if you anneal your Lapua brass, and run modest pressures, Lapua brass can perform well for 20 or more load cycles.]
The areas most affected are the case neck and case head area. Case neck walls get thicker [but] the case head area body walls get thinner. Primer pockets get shallower and larger diameter.
This case shows a cracked neck AND a crack (separation) above the case head. Zediker says it is “rare to see one case with both of the most common failures. [This case] was attacked by an M14.”
Case Head — Causes of Separation and Cracking
When a case is under pressure during firing, the brass, like water, flows where it can, where it’s more free to move. Of course, the chamber steel limits the amount it can expand. The case shoulder blows fully forward and the case base is slammed back against the bolt face. There is, therefore and in effect, a tug on both ends — it gets stretched. The shoulder area is relatively free to expand to conform to the chamber, but the other end, the case head area, is not. Since that’s the area of the case with the thickest walls, it doesn’t expand “out” much at all. What it does is stretch. The “case head area,” as I refer to it here, is the portion of the case above the web, which is just above the taper that leads in to the extractor groove. The “area” extends approximately an eighth-inch up the case body.
Here’s a “pressure ring.” You’ll see this after firing, if you see it. And, if you see it, that case is done. The bright ring indicates excessive stretching, which indicates excessive thinning. If you see a ring circling the case, noticeable because it’s lighter color than the case body, and it’s in this area, I’d say that case is done. And that’s right where a “head separation” occurs. It can crack and also blow slap in two, and that’s the “separation” part of case head separation.
Photo courtesy GS Arizona.
This is a spot to keep close watch on as cases age. It is also the area that is more “protected” by sizing with less case shoulder set-back. That is, pretty much, where the freedom for the stretching movement in this area comes from (the case shoulder creates a gap). If you’re seeing a sign that a head separation [might happen with relatively few firings], chances are the shoulder set-back is excessive, and also… the load pressure level.
Bent Paper Clip Case-Wall Gauge
Editor: You can use a bent paper clip to detect potential case wall problems. Slide the paper clip inside your case to check for thin spots. GS Arizona explains: “This simple little tool (bent paper clip) will let you check the inside of cases before you reload them. The thin spot will be immediately apparent as you run the clip up the inside of the case. If you’re seeing a shiny line on the outside and the clip is really hitting a thin spot inside, it’s time to retire the case.” Photo by GS Arizona.
Monitor Primer Pocket Dimensional Changes
Another case-head-area and pressure-related check is the primer pocket. As said, the primer pocket will get larger in diameter and shallower in depth each firing. As with many such things, the questions are “when” and “how much,” and the main thing, “how much?”
If the pocket gets excessively shallow, and that’s judged by a primer that seats fully but isn’t at least a tick below flush with the case base, there could be function issues. There’s a risk of a “slam-fire” with a semi-auto that uses a floating firing pin, and, if there is actual protrusion, that has the same effect as insufficient headspace. A primer pocket uniformer can reset the depth of a shallowed primer pocket to what it should be, but the real test for me is how easily the next primer seats into it. If it’s significantly less resistance, I’ll say that case is done. Shallower can be refurbished. That’s a primary function of a primer pocket uniformer. Larger diameter, though, can’t be fixed. I’ve mentioned in another article or two that, any more at least, my main gauge of load pressure has become how much primer pocket expansion there’s been.
Applied Ballistics has released powerful new ballistics software, the Applied Ballistics Quantum™ App. This state-of-the-art mobile App provides a complete ballistics solver plus profile management tool for long-range shooting. Featuring an all-new user interface, AB Quantum™ includes a host of new tools and features for competitive shooters and hunters.
“Ballistics can be complicated, and it is our job to simplify what’s important so that shooters can hit targets”, said Applied Ballistics Founder/Chief Ballistician Bryan Litz. “The AB Quantum platform meets this goal and more. By integrating the ballistic solver with other support tools, shooters will have a complete management system to … put rounds on target faster and easier than ever before.”
Applied Ballistics Chief Technology Officer Nick Vitalbo said that the goal was “to create the most intuitive, feature-rich ballistics application on the market, seamlessly integrating with the entire Applied Ballistics ecosystem of products. AB Quantum™ will be our flagship platform, driving the future of AB-integrated devices [and transforming] the way [customers] use their existing AB-enabled products.”
Quantum™ Ballistics App — New Features Overview
AB Quantum™ creates a new paradigm for ballistic solvers and integration with Bluetooth®-enabled devices. With a host of new features, the platform is designed to save time and add performance for users of all skill levels. The all-new user interface is designed with single-handed use in mind, putting all major features just a swipe or tap away from any screen, which allows users to rapidly obtain solutions in the field or at a match. The simplicity and versatility of the app interface creates an intuitive experience for both new and experienced users.
Two new features — AB Quantum Connect™ and AB Quantum Sync™ — enable users to quickly connect to other AB-enabled devices and sync gun profiles between them in seconds, as well as back those profiles up to an encrypted server for peace of mind and easy restoration. The new platform automatically saves changes made to rifle profiles and updates connected devices. AB Quantum™ also includes customizable Range and Multi-Target tables. After creating a range or target card, it can easily be shared via email.
AB Quantum™ platform has impressive, innovative features:
● AB Quantum™ User Interface — Take control of ballistic data and find solutions with ease using the new layout designed with one-handed operation in mind.
● New Bluetooth® Device Manager — Find and connect AB Bluetooth® devices quickly and send data
between devices using AB Quantum Connect™.
● AB Quantum Sync™ — User gun profiles are automatically uploaded to an encrypted server to allow easy access for other devices and backup, providing peace of mind and security.
● Customizable Range Card and Target Card Modes — The new expandable and customizable range and
target card modes allow users to select what data to see for each Range or Target. Use the share function to send range and data cards in just seconds.
● New Reticle Library — The AB Reticle library is hosted online and updates in AB Quantum™ automatically, providing users with up-to-date solution drawing for their favorite rifle scopes.
● Improved Truing Interface — Easy to access ballistic truing features without leaving solution screens.
● Chronograph Integration — Connect Bluetooth®-enabled chronographs – such as the Optex Systems
SpeedTracker™ – directly to the App and save the velocity data to rifle profiles.
The acclaimed Applied Ballistics Bullet Library is a good example of simplification for shooters: it includes thousands of projectile models that have been built using Doppler Radar to create a Custom Drag Model (CDM) for each bullet. This library is a core feature of the AB Quantum™ App, giving users the fastest way to create accurate and precise solutions for any environment.
Consumers can now download the AB Quantum App from iOS or Android app stores. There is a free basic version, as well as an Elite subscription, which unlocks many more features for just $2.99/month or $19.99/year (see chart below). For more information visit AppliedBallisticsllc.com/ab-quantum/.
About Applied Ballistics
Applied Ballistics provides ballistics data and software solutions for shooters, hunters and industry partners. Offering books, online training, and advanced ballistics software, Applied Ballistics is dedicated to delivering accurate, unbiased ballistics information and solutions.
Along with the 20 Monday Deals featured here, some major vendors are offering site-wide specials today, Cyber Monday, December 2, 2024. You can get FREE Shipping or FREE Hazmat. In addition, Natchez is running major discounts for the next full week through December 8, 2024. Check out these specials:
Natchez is running a major Cyber Week Sale all this week from 12/2/24 to 12/8/2024. There are discounts up to 70% Off for outdoor gear and shooting accessories. Visit NatchezSS.com for Cyber Week Savings on a vast selection of outdoor gear and shooing products — including ammo — with savings up to 70% off! NOTE: For today only, Monday December 2, 2024 you can also get FREE Shipping with orders of $99.99 or more. Use Code FS241129 for FREE Shipping.
At Sportsman’s Guide, use coupon code SG4124 at checkout to receive 15% off your entire purchase> This works for nearly everything on the site, but with these exclusions: Buyer’s Club Membership fees, Ammo, Firearms, Trolling Motors, Electronics, Night Vision Optics, Generators, Doorbusters, and Bullseye deal items. 50 maximum coupon value. The coupon cannot be combined with any other coupons and cannot be redeemed for cash. Offer expires December 3, 2024.
Get FREE HAZMAT today at Powder Valley Outdoors with an order of $99 or more. Valid Monday, December 2nd only! NOTE: This promotion excludes dealers and cannot be combined with any other offer. Order value is based on $99 of hazardous materials from the following categories: Black Powder, Powder Substitutes, Primers, and Percussion Caps.
EuroOptic is running many CyberWeek and December promotions right now. Some of the deals conclude today 12/2/2024, but other promotions run through 12/8 or even through the end of the month. If you are shopping for a premium optic or a hunting rifle, head over to EuroOptic.com today.
Today, Monday December 2, 2024, Precision Reloading is offering $5 Flat-Rate Shipping on all orders of $99 or more. Use Discount Code SHIP5 at checkout to take advantage of this one-day discount.
This is a grim tale. A man almost lost the use of his right hand, and did suffer terrible injuries to his fingers. All because he picked the wrong bottle of powder off the shelf. We have run this story before, and we will continue to run it every year, as a caution to our readers. This mistake is easy to make, but the consequences can be dire. Always, always double-check your powder labels before you start the hand-loading process. If you don’t, you may not have a hand to load with next time…
Similar Labels, Disasterous Consequences
The shooter, Denny K., was assembling some rounds for his brand new 7mm-08 Savage hunting rifle. He thought he was loading with Hodgdon Varget. Instead he had filled his powder measure with Hodgdon TiteGroup, a fast-burning pistol powder. The labels are similar, so the mistake is understandable. But the results were devastating. Here’s what 41 grains of TiteGroup can do in a 7mm-08:
Posting on the Firing Line, in a thread entitled “Lucky to Be Alive”, Denny writes:
“This is the hardest post to post. I know if I had read it a week ago my comment would have been: ‘You have no business reloading’. I had everything perfect, except pouring the wrong powder in the powder measure. I type this slowly with my left hand, embarrassed but … possibly saving someone else a tragedy or, like me, a long drive to the Emergency Room and surgery to save my finger.”
The Still-Sealed Bottle of Varget
Denny did not initially comprehend exactly why the kaboom happened. He thought maybe his new Savage rifle was at fault. Then, on his return home, he discovered something…
Denny wrote: “The seven-hour period it took to go to ER, transport to Trauma Center and surgery made me think it was a Savage rifle issue. Brand new rifle, new brass, triple-checked loading data. The next day I was humbled when I realized the Varget powder was still sealed.
I knew what powder to use. I thought [Varget] was what I used. Not until the following day did I realize the Varget was still sealed.”
At that point, Denny realized what caused the accident — “operator error”. He knew he had to warn others about using the wrong powder: “I knew I needed to share my mistake, even though it is embarrassing, just to remind people. I’ve been reloading for 30 years…”
Editor’s Comment: Denny was not a novice reloader. His experience demonstrates that this kind of mistake can be made by any hand-loader, even one with decades of experience. Be safe guys, take your time when you load your ammo. Remove powders from measures after your loading sessions (pistol powders can look very similar to rifle powders). And by all means CHECK the LABEL on the jug. As the TiteGroup label says: “A little goes a long way.”
It’s not a bad idea to separate your pistol powders from your rifle powders, or perhaps even load for pistol in a separate part of your workshop.
Today is Thanksgiving, aka “Turkey Day”, a time to enjoy an annual get-together with family and friends. To mark this occasion we offer a collection of interesting videos about turkey hunting plus a FREE Turkey target. Enjoy your Thanksgiving holiday!
GetZoneHunting.com has a vast video library for hunters, with hundreds of helpful videos on all types of hunting. In time for spring turkey season, GetZoneHunting offers a big collection of turkey hunting videos: At the Ranch – Turkey. On that page you’ll find 13 turkey hunting “how-to” videos. Here are links to five GetZone Turkey Hunting videos with valuable information from skilled, experienced hunters.
At the Ranch Turkey Hunting Videos
At the Ranch – Turkey offers solid advice for turkey hunters. These five videos will help you better understand turkey behavior and have success on your hunt. Click any photo to watch the particular video on the GetZone website. (Work Warning — When each GetZone video opens, it may immediately launch an annoying commercial with loud AUDIO!). There are eight more turkey hunting videos on GetZone’s Turkey Hunting HQ Page.
At the Ranch: Shot Placement for Turkeys — CLICK PHOTO to Watch Video
At the Ranch: Turkey Hunting Essentials — CLICK PHOTO to Watch Video
At the Ranch: The Difference Between a Jake and a Tom — CLICK PHOTO to Watch Video
At the Ranch: Early vs. Late Spring Turkey Hunt — CLICK PHOTO to Watch Video
At the Ranch: How to Plan a Turkey Hunt — CLICK PHOTO to Watch Video
Free Printable Turkey Target from AccurateShooter.com
As a special bonus for our readers, here is a free, printable Turkey Target, so you can practice for your turkey hunting adventure, This special Turkey Bullseye Target was created by our friend and Forum member Pascal (aka “DesertFrog”). CLICK HERE for FREE Turkey Target.
Caldwell Brass Retriever
Tired of bending over or kneeling down to retrieve your fired cartridge brass? For older shooters (including this Editor) getting down on the ground to pick up brass is tough on the lower back and knees. Here’s a product that makes brass retrieval quick, easy, and pain-free. The Caldwell Brass Retriever works quite well with a little practice, once you apply the correct pressure. While it won’t always grab every fired case, it will capture nearly all, and that can really make the job go much faster.
One owner praises this as a “very good tool” that is “a lot easier on my back.” While it can work on grass, gravel, and hard-packed earth, the unit works best on smooth, hard surfaces. Currently priced at $47.46 on Amazon, it is an affordable tool.
Caldwell states: “Spend less time bending over and picking up brass at the range and more time shooting. The Caldwell® Brass Retriever picks up brass, saving your back and time. The Brass Retriever can pick up rifle and pistol brass quickly and efficiently. The retriever comes complete with a roll cage separator that allows you to dump the collected brass into a bucket quickly. It is collapsible as well, making it convenient to transport. The retriever’s handle expands from 28″ up to 57″ tall.”
Brass Retriever Owner Reviews
Here are Amazon reviews from actual purchasers. It’s clear the device is not perfect and can miss a case or two. However, the Brass Retriever does grab the vast majority of brass on the ground, sized .223 Rem or larger diameter. This will save time and reduces stress on your back and joints:
“This thing … does a terrific job of collecting the brass from a standing posture quickly and efficiently. It helps to have the cases on a smooth surface like concrete or dirt without a lot of vegetation. But we used it on open desert yesterday and it collected nearly every case with a single pass. It’s now a permanent piece of gear in the stuff we take when target or ground squirrel shooting.” — Hans H.
“This WILL save your back. The only drawback is you can’t overload it with brass. After couple dozen pieces (or less) it will start dropping brass while you’re attempting to collect others. That’s the limitation (one of them). There is a short learning curve (15 min.) in which you’ll learn how much brass is too much And how you need to orientate the wires to pick up the brass. It doesn’t do as well on gravel or high grass as it does on a smooth, firm surface. Even with its limitations, it’s a keeper. Just empty every dozen or so pieces and it works very well.” — Jeff M.
Specialized Tool for .22 LR Brass
NOTE: The Caldwell Brass Retriever is designed primarily to recover reloadable rifle and pistol brass, with case diameters as fat as .223 Rem or larger. Some people state it can be used for smaller .22 LR cartridges too, but there is a much better product for that.
The UniqueTek Rimfire Brass Wizard is optimized for picking up .22 LR rimfire cases. It has a smaller basket with wires spaced closer together. It can also pick up pistol and rifle cartridge brass but will hold fewer cases than the original Brass Wizard or the Caldwell Brass Retriever. The Brass Wizard “Rimfire” The Brass Wizard “Rimfire” comes standard with the telescoping handle and includes a”Dumper” accessory.
Black Friday is the day after Thanksgiving. Around the country major shooting sports retailers will be offering significant savings on a wide variety of products — from reloading dies to complete, high-end rifles. Some of the major players, such as Brownells, Bud’s Gun Shop, and Palmetto State Armory, have already started their “Black Friday Week” sale, with discounts up to 35% on some products. With Brownells Use Promo Code 15BF to save 15% sitewide — plus you can also get FREE Shipping with $49+ orders.
Gun.Deals has also found some great Black Friday Week bargains from Amazon, as well as major online shops such as KYGUNCO, LockedandLoaded, Sportsman’s Warehouse, and more. We feature a dozen of these hot deals in the table below. Click any box to find the deal on the seller’s website. NOTE: These deals may expire quickly, so you should check often on the Gun.Deals Black Friday Specials Page.
At the request of our readers, we provide select “Deals of the Week”. Every Sunday afternoon or Monday morning we offer our Best Bargain selections. Here are some of the best deals on firearms, hardware, reloading components, optics, and shooting accessories. Be aware that sale prices are subject to change, and once clearance inventory is sold, it’s gone for good. You snooze you lose.
NOTE: All listed products are for sale to persons 18 years of age or older. No products are intended for use by minors.
1. Palmetto SA — Black Friday Guns and Optics Deals
⏺️ Save hundreds on popular AR lowers, pistols, and optics
Black Friday is the day after Thanksgiving. But Palmetto State Armory has kicked off its Black Friday Sale already. There are some absolutely amazing deals, such as a nice SAR9 Pistol complete with holster and belt mag holder for just $249.99. Or get a complete AR lower for just $149.99. If you enjoy rimfire pistol shooting, grab the Taurus TX22 pistol for $219.99 ($75 Off) and get 3 extra magazines via a Taurus rebate.
2. EuroOptic — Bergara Hunting Rifle Clearance
⏺️ Significant savings on Bergara B-14 Wilderness Series rifles
If you want a nice bolt-action hunting rifle at a big discount, check out Closeout Bergara rifles at EuroOptic. Bridging the gap between the B-14 basic and Premier Series, Bergara’s B-14 Wilderness Series is on sale, with featured Hunter ($751.99 on sale) and Terrain ($976.99 on sale) models. These rifles offer good ergonomics and hand-painted camouflage stocks with webbing for increased texture and grip. All Wilderness Series barreled actions feature Sniper Grey Cerakote finishes for advanced protection in extremely harsh weather.
3. Midsouth — LEE Anniversary Press and Dies, $79.99
⏺️ Solid single-stage press AND die set under $80!
The LEE Challenger is the world’s best-selling single station press. The latest Gen III Challenger features an ergonomic lever plus a convenient tube for spent primers. Right now, to mark its 40th Anniversary, LEE is offering a FREE die set with the purchase of the LEE Gen III Challenger Press. Choose one of five cartridge types: .223 Rem, 9mm Luger, .38 SPL/.357 Mag, .44 SPL/.44 Mag, and .45 ACP. A great feature of the LEE Press is the Breech Lock Quick Change Die System — change dies instantly with a twist of the wrist.
4. Ammo Depot — Huge Ammo Sale
⏺️ Major savings on quality 9mm and .223 Rem ammo
Save big bucks right now with the pre-Black Friday Ammo Sale at Ammo Depot. You’ll find top quality ammo from major brands at up to 80% savings. Plus there are range pack discounts for larger quantities — 200 to 5250 rounds. We noted many very great deals on 9mm pistol ammo and .223 Rem (5.56) ammo, with a variety of bullet types.
⏺️ Many positive user reviews — good set-up for varminting and home ranges
Need a good platform for shooting in areas other than organized ranges? Check out the Caldwell Stable Table Deluxe. A bolt in the base allows position adjustment of a single leg, aligning the tabletop so that it is parallel with the horizon. The central shaft, seat, and tabletop are able to pivot (rotate) around a center axis as a single unit while keeping the tabletop parallel to the horizon. This is great for varmint hunting. Owner reviews have been very positive. This item is sold via Walmart.com but ships from Optics Planet.
⏺️ Great value and good choice for PRS/NRL and tactical matches
Need a quality scope at an affordable price for your PRS/NRL rifle? Check out the Vortex 4-24x50mm MRAD Scope at MidwayUSA. Now on sale for just $299.99 (40% off), this quality tactical scope features 0.1 mil click values and EBR4 MRAD-type reticle for easy hold-overs and wind adjustments. Proprietary coatings increase light transmission and the Illuminated reticle provides precise aiming under low-light conditions. Now $200 off the regular $499.99 price, this is a super scope steal.
7. Amazon — Magpul MOE Bipod, $56.93
⏺️ Rugged, reliable bipod that is strong, yet light weight
Whether hunting, competing, or just having fun at the range, having a quality bipod is important. We like the Magpul MOE Bipod which is available in black or FDE. At 8 ounces, it weighs almost 40% less than some other bipods while still providing a dependable, stable platform to shoot from. Staggered soft rubber feet hold fast on a variety of shooting surfaces and are easily removed should users choose to change feet. The bipod legs accept most Atlas-pattern bipod replaceable feet.
8. Amazon — Night Vision Binoculars, $99.97
⏺️ Top-seller with 4k HD image that can be recorded
Here is a great product for hunters that can also serve for home security, allowing you to scan your property at night. These Hexeum 4K Night Vision Binoculars can “watch live” as well as record stills and video. Now available for just $99.97, these view-screen binoculars can take high definition photos and record/playback video in daytime or night time. The recording is 4K HD quality with playback via a 3″ wide view screen. This unit is Amazon’s #1 Best-Seller among Night Vision Binoculars and Goggles. This Hexeum unit comes with a 32GB storage card and offers USB Type-C fast charging.
⏺️ Get TWO good compact lock boxes for home or when traveling
Keeping handguns safe from theft or unauthorized use is vital. One good travel option is the TSA-compliant STOPBOX Gun Safe lock box. The button-activated mechanical lock offers quick access to your firearm. This lock box is also padlock-compatible. This $159.00 deal gives you TWO portable handgun safes, each measuring 9.25″ x 7.15″ x 1.75″ inside — big enough to handle full-size pistols. The patented glass-reinforced polycarbonate ABS and steel-reinforced lock boxes pass tough drop tests and come with a limited lifetime warranty.
With noticeable movement and loud sound at each hit, shot impacts can be heard and seen on the Birchwood Casey Boomslang AR500 Steel Gong even at considerable distance. This portable target is easy to set up and is rated for centerfire handguns and centerfire rifles up to a big .338 Magnum rifles. Note: When using the target, handguns require a minimum distance of 25 yards. With rifles, place the Boomslang target no closer than 100 yards.
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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.
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.
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.
NOTE: There are ten (10) shots in the group, but for simplicity we are only displaying five (5) shot circles. Adding more circles won’t change the measurement because the two most distant shots, which determine group size, ARE included.
What kind of 200-yard accuracy can you get in an enclosed, underground test range? Would you believe 0.162 MOA at 200 yards with a .338? Have a look at these test targets from Sierra Bullets. Like most bullet manufacturers, Sierra does live-fire bullet testing to ensure that Sierra projectiles perform as promised, with repeatable accuracy. Sierra tests bullets in its own underground test complex. Sierra’s 300-meter test range is the longest, privately-owned underground bullet test facility in the Western Hemisphere.*
Day in and day out, various bullet types are tested using a big collection of barreled actions. These barreled actions are clamped in stout, return-to-battery test fixtures. These big, heavy test fixtures provide near-perfect repeatability (with no human-induced holding or aiming errors).
Sierra Bullets 10-Shot Groups at 200 yards
Check out these 10-shot test groups shot at the Sierra Test Range at 200 yards. Note that the numbers listed on each sample are actual measurements in inches. To convert to MOA, cut those numbers in half (to be more precise, divide by 2.094, which is 1 MOA at 200 yards). For example, the 0.340″ middle group works out to 0.162 MOA at 200 yards.
Scan-Verified 0.162 MOA Accuracy at 200 Yards
To verify the accuracy of Sierra’s measurements, we measured the middle (.338 caliber) 10-shot group with our On-Target Group Measurement software. We registered a group size reading of 0.339″ — within one-thousandth of the Sierra measurement. The calculated group size in MOA (Minute of Angle) is 0.162.
That’s amazingly good for ten rounds of big .338 caliber bullets. A FIVE-shot 0.162 MOA group at 200 would be considered excellent at any benchrest match. But remember this target has TEN shots. The current, one-target IBS world record for ten shots at 200 yards is 0.245″, set by Ed Watson in 1999.
Bevy of Barreled Actions for Bullet Testing
Sierra Bullets uses dozens of barreled actions for testing bullets in its enclosed, 200-yard test range. Each barrel has its own logbook to track the barrel’s usage.
Click Photo to Zoom
*Even Longer Test Tunnels Exist in Europe: At Stadeln in Germany, RWS (now part of RUAG) owns a 500 meter tunnel (above ground level) which has existed for decades. In Thun, Switzerland, RUAG has a fully-instrumented 500 meter underground tunnel. Near Ulm, Germany, there is a 5-lane 300 meter underground shooting range that is open to the public.
Hybrid Bullet Design — Best of Both Worlds?
Scan-Verified 0.162 MOA Accuracy at 200 Yards
