For this Sunday GunDay article we feature a “blast from the past” — David Tubb’s engineering tour de force, the Tubb 2000, or “T2K” for short. With the remarkable T2K, David earned multiple NRA High Power championships, and David shot the first-ever perfect score in the NRA Long-Range “any sights” championship 16 years ago.
Our write-up this week focuses mostly on “hardware” because David’s performance with the rifle speaks for itself. He has won eleven High Power National Championships at Camp Perry, and in 2004 David mounted a scope to his rifle and captured the Long-Range “any sights” Championship with a 1450/1450, the first and only perfect score ever logged at Camp Perry. He did this all with his trusty 6XC-chambered T2K, shooting the DTAC 115gr bullet in a 1:7.5″-twist Schneider P5 barrel. For more information about this remarkable competition rifle, read on.
[Editor’s NOTE: Because this is an article from our older Archives, some technical details may have changed with time. For all current specifications on TUBB rifles, including the TUBB 2000, visit DavidTubb.com. For more information on the particular T2K rifle featured in this story, CLICK HERE.]
Mag-Feed Action with Unique Bi-Camming Bolt
The action is machined from 17-4 stainless steel to true benchrest quality standards. The design features a solid top with a loading port. This increases action stability, stiffness, and strength. The loading port is easily accessible and is angled to aid the shooter in single loading rounds. The Tubb 2000 is fed via 10- or 20-round box magazines.
“I prefer using 20-round magazines with the Tubb 2000 because it provides a secure hand hold when shooting off the bipod. For across the course competition, the 10-round magazines are the best choice as they do not encumber sling-supported shooting positions. There is no difference in the functioning or reliability of either capacity magazine.”
One-finger Bolt Operation
Low effort bolt operation was a key goal in the design of the Tubb 2000 action. The exclusive bi-camming design employs two cams that engage during bolt lift to radically reduce bolt lift effort. Bolt lift is 75 degrees. The cone-faced bolt has two locking lugs which are narrower and taller than on conventional actions. This design allows the magazine to be mounted higher in the action for smoother, more positive feeding. The bolt handle is designed for superior performance in sustained fire operation. Its ergonomic shape allows operation with a single finger, if desired. The bolt is machined from 8620 carbon steel and rides back into the butt extension, under the shooter’s face so the bolt can be operated without the shooter having to change his head position. This low center of gravity also improves the rifle’s feel and performance under recoil.
The action features a full-length Picatinny rail that will accept Weaver®-style mounts. The action’s adjustable sight mounting system allows the rail to be mounted at one of three pre-set mounting angles — 0, 5, and 10 degrees — to allow the shooter to level the sights to fit his shooting style. A custom base is available to mount match iron sights. All barrels have a small section at the muzzle turned down to accept a clamping-style front sight mount or cant indicator.
The T2K’s Lock Time is ONE millisecond — over three times faster than a Model 70 Winchester.
Barrel Configuration
Tubb 2000 rifles featured hand-lapped stainless steel match barrels with the exclusive “Tubb Contour.” This unique contour maximizes accuracy and minimizes weight — it’s the perfect balance. According to David: “It’s a contour where the barrel wouldn’t shoot one bit better if it was one bit bigger.” The Tubb 2000 was conceived as a “switch barrel” gun — it’s designed to be easily re-barreled by the customer. This feature means that the same rifle can support different calibers and shooting disciplines. Finished barrels in a variety of calibers were available for “do-it-yourself” installations. The gun shown here has a Schneider barrel.
The Tubb 2000 has, over the years, been offered in a variety of chamberings including: .22-250; .243 Winchester; 6mmBR Norma (6BR); 6XC; .260 Remington; 7mm-08; and .308 Winchester. Available accessories include finished barrels, extra 10- or 20-round magazines, cleaning rod guide, adjustable bipods, custom adjustable handstop, fore-end weight rail, and cant indicator.
Trigger, Stock Adjustment and Other Features
The Tubb 2000 uses the superb Anschütz® fully-adjustable two-stage trigger (with safety); one of the finest available to the precision rifleman. This trigger can also be adjusted to provide single-stage operation. The buttstock assembly, forend, buttstock clamping block, and magazine housing, trigger guard assembly are made from 60-series aluminum, hard anodized in the customer’s choice of 6 colors: light and dark teal, purple, red, forest green, and black. (The T2K Tactical (see below) comes in matte black only.) These four parts are each available in any of the listed colors, allowing the purchaser to design his own distinct rifle.
The buttstock is FULLY adjustable for length, height, cant (angle), and offset. The cheekpiece is adjustable for height. An easily accessible knurled wheel allows the shooter to adjust the cheekpiece from the shooting position. Shooter comfort is further augmented by an ergonomic pistol grip. All adjustment features on the Tubb 2000 were designed for easy shooter access. The butt extension, clamping block, shock housing, and buttplate all have index marks to allow the shooter to record and repeat adjustment settings. The tubular fore-end can be rotated and positioned to accommodate the shooter’s preference. An integral accessory rail accepts a custom adjustable handstop or bipod. The fore-end also incorporates a built-in barrel heat wave blocking system which eliminates optical distortion in the sighting plane.”
David Tubb Explains T2K Stock Adjustments
I advocate setting stock length a little longer than most people might. I am a firm believer that it is best to “reach” slightly for the pistol grip as this ensures a strong, secure hold on the rifle. I pull the rifle firmly into my shoulder pocket when shooting offhand, and also prefer to have what I would characterize as very firm contact between rifle butt and shoulder in the sitting and prone positions as well. When using a sling in prone or sitting, stock length (and sling tension) should be great enough so that, at the least, you have to push the buttpad forward with your hand in order to place the stock into the shoulder pocket. My buttstock is shortest offhand and longest prone. If my standing setting is “0”, I’m usually out about 1-1/2 inches for sitting and about another inch for prone. I have found that many people tend to shoot with a stock that’s too long in sitting and too short everywhere else.
I have found the cast off/on adjustment feature on the buttstock to be of great help to me in attaining the natural shooting positions I desire. For prone, I offset the clamping block so the buttplate moves outward [the index mark on the clamp is to the right of center on the scale on the receiver extension tube]. I swing it a little bit inward for offhand and slightly more inward for sitting. The amounts of cast on/off (in clock-face terms) are approximately 6:30 for standing, 4:30 for prone, and 8:00 o’clock for sitting.
Stock Length Adjustment Procedure
The buttstock is adjustable in length 4+ inches. This adjustment is accomplished by moving the buttplate tube in or out after loosening the four screws on the clamping block. Ensure that the buttstock tube is fully contained in the block. The extent of rearward (lengthening) movement is determined by the front of the buttstock tube fitting flush with the front of the block.
Stock Cast and Cant Adjustment Procedure
The buttstock is adjustable for cast or offset by loosening the four screws on the clamping block and swiveling the block on the receiver extension tube. The buttplate itself is adjustable for cant up to 360 degrees and after loosening the screw directly in the center of the rubber recoil pad is adjustable for height at approximately 1-1/2 inches. The cheekpiece is adjustable vertically approximately one inch. The vertical cheekpiece adjustment is accomplished via the top knurled ring. The lower knurled ring will then secure the setting.
About David Tubb — Tubb 2000 Designer
David Tubb is arguably the winningest centerfire rifleman in history. He has won a record eleven NRA National High Power Rifle Championship titles at Camp Perry, along with six NRA Long Range HP Championships. In addition, David is an NRA Silhouette Rifle legend, having won nearly 30 open, individual National Championship titles in all four rifle categories. David has also won seven Sportsmen’s Team Challenge Championships and multiple Wimbledon Cups. His latest big win was the 2019 NRA ELR Championship in Heavy Gun Class.
For more information on the
Tubb 2000 Rifle contact:
David Tubb Accuracy
and Precision Gun Parts
800 N. 2nd Street
Canadian, TX 79014 DavidTubb.com
Phone: (806) 323-9488
Forum member Danny Reever and this Editor have discussed how novice reloaders can struggle with the fine points of reloading, making errors in seating depth, neck-bushing choice, or sizing their cases. We agreed that a good resource covering more than “Reloading Basics” is sorely needed. Danny reminded me that Glen Zediker’s excellent Handloading for Competition book has been available since 2002. Danny says this may still be the best guide in print for those getting started in precision reloading, though the book is not without flaws.
Danny observed: “I consider this still the best book out there on the subject. I’ve bought a lot of other books only to be sorely disappointed after spending $30-$40 of my hard-earned cash. This book is not one of those! I’ve read and re-read Zediker’s treatise at least four times and refer to it often for advice while reloading. My number one suggestion for those who buy the book is to sit down with a highlighter and read it cover to cover. It’s well-written with a bit of humor and it is not boring.”
Extremely comprehensive, Zediker’s book covers nearly all of the key factors involved in accurate reloading: case sorting, brass prep, load development, neck-sizing, full-length sizing, bushing selection/use, tool selection, priming, powder measurement, and bullet seating. The book also explains how to test and evaluate your ammo, and how to monitor and interpret pressure signs.
There are many “must-read” sections in Zediker’s book, according to Danny: “The section beginning on page 161 dealing with concentricity (and how to achieve it) is excellent. Likewise the Load Limits section discussing pressures offers very valuable advice and info. You should also read Zediker’s commentaries about load testing, powders (burn characteristics etc.), and the effects of temperature.”
Zediker has conveniently provided a detailed summary of his book on the web, complete with table of contents, sample pages (PDF format), and dozens of illustrations. Shown above is just one small section that covers ejectors.
Overall, we recommend Glen Zediker’s Handloading for Competition, though the book definitely could use some updating. Danny says: “Plunk down the [money] and buy this book, you won’t be sorry.” Zediker’s book is available from Amazon.com ($34.99), Midsouth Shooters ($33.49), and Zediker Publishing ($36.95).
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Here is an article Glen Zediker wrote for the Midsouth Blog. In this article Glen gives important advice on selecting, handling, seating, and testing primers. The right primer choice can and will affect your load’s performance and accuracy. And proper primer handling is essential for safety.
by Glen Zediker
The primer is one component in the collection that might not get all the attention it warrants. That’s because it is the one thing, above all other components, that you don’t want to just swap and switch around. We’ve all heard cautions about testing new lots of every component, especially propellant, but primers not only change lot to lot, they vary greatly in their influence on any one load, brand to brand.
The difference in one brand to the next can equal a good deal more or less pressure, for instance. While there are “general” tendencies respecting the “power” of various-brand primers, always (always) reduce the load (propellant quantity) when switching primers.
This has become more of an issue over the past few years as we’ve faced component shortages. I can tell you without a doubt that going from a WW to a CCI, or from a Remington to a Federal, can have a major influence on a load. I establish that from chronograph readings. No doubt, it’s best to have a good supply of one primer brand and lot that produces good results, and when that’s not possible, it’s a hard sell to convince someone to stop loading ammo and get back to testing. But. It is important. I can tell you that from (bad) experience. How I, and we all, learn most things…
When I switch primers, whether as a test or a necessity, I reduce my load ONE FULL GRAIN. There can be that much effect.
The Elements of a Primer
A primer is made up of a brass cup filled with explosive compound (lead styphate). Lead styphate detonates on impact. Primers don’t burn – they explode! In the manufacturing process, this compound starts as a liquid. After it’s laid into the cup, and while it’s still wet, a triangular piece or metal (the “anvil”) is set in. When the cup surface is struck by the firing pin, the center collapses, squeezing the explosive compound between the interior of the cup and the anvil. That ignites the compound and sends a flame through the case flash hole, which in turn lights up the propellant.
Primers Can be Dangerous — Particularly When Stacked
Don’t underestimate that. I’ve had one experience that fortunately only created a huge start, but I know others who have had bigger more startling mishaps. These (almost always) come from primer reservoirs, such fill-tubes. Pay close attention when charging up a tube and make sure all the primers are facing the right way, and that you’re not trying to put in “one more” when it’s full! That’s when “it” usually happens. What will happen, by the way, is akin to a small grenade. Static electricity has also been blamed, so keep that in mind.
Sizes and Types of Primers
Primers come in two sizes and four types. “Large” and “small”: for example, .223 Rem. takes small, .308 Win. takes large. Then there are pistol and rifle in each size.
Rifle primers and pistol primers are not the same, even though they share common diameters! Rifle primers [normally] have a tougher cup, and, usually, a hotter flash. Never swap rifle for pistol. Now, some practical-style competitive pistol shooters using their very high-pressure loads (like .38 Super Comp) sometimes substitute rifle primers because they’ll “handle” more pressure, but they’ve also tricked up striker power. That’s a specialized need.
Further, some primer brands are available with a “magnum” option. Some aren’t. My experience has been that depends on the “level” of their standard primer. A magnum primer, as you might guess, has a more intense, stouter flash that travels more “deeply” to ignite the larger and more dense powder column. It reaches further, faster.
Flash Consistency Counts Flash Consistency is very important, shot to shot. The consistency of every component is important: bullet weights, diameters, case wall thicknesses, and all the way down the list. We’re hoping to get more consistent behavior from a “match” or “benchrest” primer, and we’re paying more for it. I can tell you that some brands that aren’t touted as “match” are already consistent. That all comes from experience: try different primers, just respect the need to initially reduce the load for each test.
Primer Dimensional Differences and Primer Tools
One last thing — there are small variations in primer dimensions (heights, diameters) among various brands. These variations are not influential to performance. However — small diameter variations can influence feeding through priming tools. This can be a hitch especially in some progressive loading machines. Manufacturers usually offer insight (aka: “warnings”) as to which are or aren’t compatible, so find out.
This article is adapted from Glen’s books, Handloading For Competition and Top-Grade Ammo, available at Midsouth HERE. Learn more about Glen’s books at ZedikerPublishing.com.
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The anvil is the tripod-shaped thin metal piece protruding above the bottom of the primer cup. Getting the primer sitting fully flush on the bottom of the case primer pocket, without crunching it too much, requires some keen feel for the progress of primer seating.
In two informative Midsouth Blog articles, Glen Zediker offers helpful advice on priming. First he examines what happens to the primer itself as it is seated in the cup. Glen explains why some “crush” is important, and why you never want to leave a high primer. Glen also reviews a variety of priming tools, including his favorite — the Forster Co-Ax Bench Primer Seater. Then he offers some key safety tips. Glen provides some “rock-solid” advice about the priming operation. You’ll find more great reloading tips in Glen’s newest book, Top-Grade Ammo, which we recommend.
Priming Precision vs. Speed
Glen writes: “The better priming tools have less leverage. That is so we can feel the progress of that relatively very small span of depth between start and finish. There is also a balance between precision and speed in tool choices, as there so often is.”
Benchtop Priming Tools — The Forster Co-Ax
Glen thinks that the best choice among priming options, considering both “feel” and productivity, may be the benchtop stand-alone priming stations: “They are faster than hand tools, and can be had with more or less leverage engineered into them. I like the one shown below the best because its feeding is reliable and its feel is more than good enough to do a ‘perfect’ primer seat. It’s the best balance I’ve found between speed and precision.”
Load Tuning and Primers
Glen cautions that you should always reduce your load when you switch to a new, not-yet-tested primer type: “The primer is, in my experience, the greatest variable that can change the performance of a load combination, which is mostly to say ‘pressure’. Never (never ever) switch primer brands without backing off the propellant charge and proving to yourself how far to take it back up, or to even back it off more. I back off one full grain of propellant [when I] try a different primer brand.”
Priming Safety Tips by Zediker
1. Get a good primer “flip” tray for use in filling the feeding magazine tubes associated with some systems. Make double-damn sure each primer is fed right side up (or down, depending on your perspective). A common cause of unintentional detonation is attempting to overfill a stuffed feeding tube magazine, so count and watch your progress.
2. Don’t attempt to seat a high primer more deeply on a finished round. The pressure needed to overcome the inertia to re-initiate movement may be enough to detonate it.
3. Don’t punch out a live primer! That can result in an impressive fright. To kill a primer, squirt or spray a little light oil into its open end. That renders the compound inert.
4. Keep the priming tool cup clean. That’s the little piece that the primer sits down into. Any little shard of brass can become a firing pin! It’s happened!
The February 2013 edition of Shooting Sports USA magazine has an interesting feature by Glen Zediker. In this Transporting Success, Part I article, Zediker explains the advantages of loading at the range when your are developing new loads or tuning existing loads. Glen, the author of the popular Handloading for Competition book, discusses the gear you’ll need to bring and he explains his load development procedure. In discussing reloading at the range, Glen focuses on throwing powder and seating bullets, because he normally brings enough sized-and-primed brass to the range with him, so he doesn’t need to de-prime, re-size, and then re-prime his cases.
Zediker writes: “Testing at the range provides the opportunity to be thorough and flexible. You also have the opportunity to do more testing under more similar conditions and, therefore, get results that are more telling. Once you are there, you can stay there until you get the results you want. No more waiting until next time.”
Zediker starts with three-shot groups: “I usually load and fire three samples [with] a new combination. I’ll then increase propellant charge… based on the results of those three rounds, and try three more. I know that three rounds is hardly a test, but if it looks bad on that few, it’s not going to get any better.”
Glen reminds readers to record their data: “Probably the most important piece of equipment is your notebook! No kidding. Write it down. Write it all down.”
There’s More to the Story…
Editor’s Note: In Zediker’s discussion of loading at the range, he only talks about throwing powder and seating bullets. In fact, Glen opines that: “there is little or no need for sizing.” Well, maybe. Presumably, for each subsequent load series, Zediker uses fresh brass that he has previously sized and primed. Thus he doesn’t need to de-prime or resize anything.
That’s one way to develop loads, but it may be more efficient to de-prime, re-size, and load the same cases. That way you don’t need to bring 50, 80, or even 100 primed-and-sized cases to the range. If you plan to reload your fired cases, you’ll need a system for de-priming (and re-priming) the brass, and either neck-sizing or full-length sizing (as you prefer). An arbor press can handle neck-sizing. But if you plan to do full-length sizing, you’ll need to bring a press that can handle case-sizing chores. Such a press need not be large or heavy. Many benchresters use the small but sturdy RCBS Partner Press, on sale now at Amazon for $77.99. You may even get by with the more basic Lee Precision Compact Reloading Press, shown in Zediker’s article. This little Lee press, Lee product #90045, retails for under $35.00.
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Looking to shoot an AR-platform rifle out past 500 yards? Then you should read two articles by AR guru Glen Zediker. Author of The New Competitive AR-15 and The Competitive AR15 Builders Guide, Zediker is an expert when it comes to AR-platform rifles. Glen believes ARs have excellent long-range capability, provided they are built to high standards, with good barrels.
Glen says: “a properly configured AR-15 is easily capable of good performance at 500+ yards. Good performance means it can hit a 1-foot-square target all the time. Competitive shooters can cut that standard in nearly half (the X-Ring on an MR1 600-yard NRA High Power Rifle target is 6 inches, and high X-counts are commonplace among more skilled shooters).”
Published in the Cheaper than Dirt Shooter’s Log, Zediker’s articles first cover the history of the AR-15, and then explain how AR-platform accuracy can be optimized. Part One reviews the AR’s development as an accurate firearm, tracing its evolution from a Vietnam-era combat weapon to what is now a favored target rifle of High Power competitors. READ PART ONE.
Part Two discusses the specifics that make an AR accurate at 500 yards and beyond. Zediker talks about barrel configuration (profile and twist rate), bullet selection, floating handguards, and proper mounting of optics or iron sights. READ PART TWO.
Barrel Twist Rate
To stabilize anything longer than a 68- or 69-grain bullet, the barrel twist rate must be — at minimum– 1-in-8. Twist rates reflect how far the bullet travels along the lands or rifling to make one complete revolution. So, 1-in-8 (or 1-8, 1:8) means “one turn in eight inches.” I think it’s better to go a little faster in twist. There is nothing wrong with a 1:7 twist. The 90-grain bullets require a 1:6.5, and that is getting on the quick side. If you want to shoot Sierra 77s or equivalent, and certainly anything longer, 1:8 is necessary. By the way, it is bullet length, not weight, which constitutes the necessary twist rate to launch a stable bullet.
Optics Mounting
Correct optical sight positioning can be a challenge. With a flattop upper, I need a good inch additional forward extension at the muzzle side of the upper for the sight mount bases to avoid holding my head “back” to get the optimal view through the scope. A longer rail piece is necessary for my builds as a result.
Buttstock Length and Adjustment
An adjustable buttstock is valuable, and even more valuable if it’s well-designed. Mostly, a standard stock is too short, and the cheek area sits too low. Adding length helps a lot by itself. There are assemblies that replace the standard buttplate to allow for length and, usually, height and rotation adjustments for the buttpad. An elevation-adjustable cheekpiece is a big help to attain a solid position.
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by Glen Zediker
Most good shooters use mirage as their leading indicator to spot changes in the wind. With well-designed stand, the scope can be set it up where you can see the wind with the left eye and see the sight with the right without anything more than a visual focus shift. That gets the shooter back on the trigger with the least chance of missing another change. In the photo below e you can see 11-time National High Power Champion David Tubb using a spotting scope set up for his left eye.
David Tubb sets up his spotting scope so he can easily see through it with his LEFT eye, without shifting his head and body position.
There are resources that give clues or evidence of wind direction and strength: wind flags, observation of grass and trees, and mirage.
Almost always I use mirage as my leading indicator. Mirage (heat waves) is always present but you’ll need a scope to read it. For 600 yards I focus my scope about halfway to the target. Mirage flows just like water and the currents can be read with respect to wind speed as well, but it’s not clearly accurate beyond maybe a 15 mph speed. The thing is that mirage shows changes, increases or decreases, and also direction shifts, really well.
A couple more things about mirage flow: when mirage “boils,” that is appears to rise straight up, either there’s no wind or the scope is dead in-line with wind direction. And that’s a quick and accurate means to determine wind direction, by the way, move the scope until you see the boil and note the scope body angle. Here’s another tip — the boil can predict when a “fishtail” wind is about to change, a boil precedes a shift.
You don’t need to spend big bucks for an effective spotting scope to view mirage. You can get the Vortex 20-60x60mm Diamondback angled spotting scope for just $399.99 from Midsouth. That’s complete with 20-60X zoom eyepiece. Though inexpensive, the Vortex Diamondback is popular with many competitive shooters and hunters. No, it doesn’t offer the sharpness of an 80mm Kowa Prominar or Swarovski spotting scope, but you’ll pay $2400+ just for the body of those high-end optics.
Choice of EyePiece — Wide-Angle LERs Work Well
I use a long-eye-relief 20X to 25X wide-angle eyepiece. That setup shows the flow best. And pay attention to where the wind is coming from! See what’s headed your way, because what’s passed no longer matters. That’s true for any indicator. Right to left wind? Read off the right side of the range.
Once I get on target then all I am doing is watching for changes. It’s really uncommon to make a big adjustment between shots. The fewer condition changes you are enduring, the easier it is to keep everything on center. That’s why I shoot fast, and why I start at the low point in a wind cycle.
Making Corrections with Limited Sighters
Here’s a Tip for NRA High Power matches where only two sighters are allowed: “Make a full correction off the first sighting shot location! Even if there are minor changes afoot, that’s how to know how well you assessed condition influence pre-shot. Don’t second-guess. After the second sighter you should be on target and then simply watching for changes. Pay attention, correlate visible cues to the results of prior shots, and if in doubt, click into the wind.”
Information in this article was adapted from material in several books published by Glen Zediker and Zediker Publishing. Glen is an NRA High Master who earned that classification in NRA High Power Rifle using an AR15 Service Rifle. For more information and articles visitZedikerPublishing.com.
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It’s the holiday season — there’s no better time to get a good gun book. Amazon has hundreds of great gun titles, while Midsouth Shooters carries a good selection line of shooting and reloading books, many of which are ON SALE this week. Looking for reliable reference works on reloading, or a gift for a shooting buddy? Check out the recommended titles below. Match directors take note — books make great match prizes. Paperback books cost no more than wood plaques but they will provide valuable information for years instead of just gathering dust in a closet. If your club offers training programs, Amazon and Midsouth offer many titles that will help new shooters improve their skills.
Noted gun writer Glen Zediker (author of Top Grade Ammo), regularly contributes tech articles to the Midsouth Shooters Blog. One of Glen’s Midsouth Blog articles covers Bullet Design. We suggest you read the article — even seasoned hand-loaders will learn a few things about projectile properties (and how to choose the right bullet design for your needs). Glen also wrote a recent Blog article on cartridge pressure signs, linked below
Glen explains: “A ‘match’ bullet’s job is to perforate a piece of paper. A bullet designed for varmint hunting, on the other hand, is designed to produce explosive impact, and one for larger game hunting strives to strike a balance between expansion and penetration. However! No matter how it’s built inside, there are universal elements of any bullet design, and those are found on the outside.”
In his article, Glen identifies the key elements of a bullet and explains how they are defined: “Base, that’s the bottom; boat-tail, or not (flat-base); shank, portion of full-caliber diameter; ogive, the sloping ‘nosecone'; tip, either open or closed (open it’s called the ‘meplat’). The shape of the ogive and the first point of ‘major diameter’ are extremely influential elements. The first point of major diameter can vary from barrel brand to barrel brand because it’s the point on the bullet that coincides with land diameter in the barrel — the first point that will actually contact the barrel as the bullet moves forward. When there’s a cartridge sitting in the rifle chamber, the distance or gap between the first point of major diameter and the lands is called ‘jump’, and, usually, the less there is the better.”
Ogives Analyzed — Tangent vs. Secant Bullet Designs
Glen notes that bullet designs reflect secant or tangent profiles, or a combination of both: “The two essential profiles a bullet can take are ‘secant’ and ‘tangent’. This refers to the shape of the ogive. A tangent is a more rounded, gradual flow toward the tip, while a secant is a more radical step-in, more like a spike. Secants fly with less resistance (less aerodynamic drag), but tangents are [often] more tolerant of jump [or to put it another way, less sensitive to seating depth variations].”
Glen adds: “Ogives are measured in ‘calibers’. That’s pretty simple: an 8-caliber ogive describes an arc that’s 8 times caliber diameter; a 12-caliber is based on a circle that’s 12 times the caliber. The 8 will be a smaller circle than the 12, so, an 8-caliber ogive is more ‘blunt’ or rounded. Bullets with lower-caliber ogives are more tolerant of jump and (usually) shoot better, easier. Higher-caliber ogives [generally] fly better, farther. This is an important component in the ‘high-BC’ designs.”
Learn More in Zediker Books
Glen has authored a number of excellent books for hand-loaders and competitive shooters. Here are three of his most popular titles, including his latest book, Top Grade Ammo:
All these titles are available from Midsouth Shooters Supply. Click each cover above to purchase from Midsouth.
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Here’s an extreme range of .224-Caliber bullets: 35gr varmint bullet and 90gr match bullet. Of course, along with bullet length/design, you need to consider MV when choosing twist rate.
Even with the same caliber (and same bullet weight), different bullet types may require different rates of spin to stabilize properly. The bullet’s initial spin rate (RPM) is a function of the bullet’s muzzle velocity and the spin imparted by the rifling in the barrel. You want to ensure your bullet is stable throughout flight. It is better to have too much spin than too little, according to many ballistics experts, including Bryan Litz of Applied Ballistics. Glen Zediker has some basic tips concerning barrel twist rates and bullet stability. These come from his latest book, Top Grade Ammo.
Choosing the Right Twist Rate
I’d always rather have a twist too fast than not fast enough. Generally… I recommend erring toward the faster side of a barrel twist decision. 1:8″ twist is becoming a “new standard” for .224 caliber, replacing 1:9″ in the process. The reason is that new bullets tend to be bigger rather than smaller. Don’t let a too-slow twist limit your capacity to [achieve] better long-range performance.
Base your next barrel twist rate decision on the longest, heaviest bullets you choose to use, and at the same time realize that the rate you choose will in turn limit your bullet choices. If the longest, heaviest bullet you’ll shoot (ever) is a 55-grain .224, then there’s honestly no reason not to use a 1:12″. Likewise true for .308-caliber: unless you’re going over 200-grain bullet weight, a 1:10″ will perform perfectly well.
Bullet Length is More Critical than Weight
Bullet length, not weight, [primarily] determines how much rotation is necessary for stability. Twist rate suggestions, though, are most usually given with respect to bullet weight, but that’s more of a generality for convenience’s sake, I think. The reason is that with the introduction of higher-ballistic-coefficient bullet designs, which are longer than conventional forms, it is easily possible to have two same-weight bullets that won’t both stabilize from the same twist rate.
Evidence of Instability
The tell-tale for an unstable (wobbling or tumbling) bullet is an oblong hole in the target paper, a “keyhole,” and that means the bullet contacted the target at some attitude other than nose-first.
Increasing Barrel Length Can Deliver More Velocity, But That May Still Not Provide Enough Stability if the Twist Rate Is Too Slow
Bullet speed and barrel length have an influence on bullet stability, and a higher muzzle velocity through a longer tube will bring on more effect from the twist, but it’s a little too edgy if a particular bullet stabilizes only when running maximum velocity.
My failed 90-grain .224 experiment is a good example of that: I could get them asleep in a 1:7″ twist, 25-inch barrel, which was chambered in .22 PPC, but could not get them stabilized in a 20-inch 1:7″ .223 Rem. The answer always is to get a twist that’s correct.
These tips were adapted from Glen’s newest book, Top-Grade Ammo, available at Midsouth. To learn more about this book and other Zediker titles, and read a host of downloadable articles, visit ZedikerPublishing.com.
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Close-up view of a sectioned case. This one here was “fixin’ to pop”, says Glen Zediker.
Here are highlights from an article Glen Zediker wrote for the Midsouth Blog. In this article Glen focuses on cartridge brass. Glen discusses the most common failures that appear with brass that has been shot multiple times, or which has been fired at excessive pressures. Glen explains some simple ways to check your cartridge brass to detect “early warning signs” of case failure, particularly case head separation, which can be 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.
Glen’s books, Handloading For Competition and Top-Grade Ammo, are available at Midsouth HERE. For more information about other books by Glen, visit ZedikerPublishing.com
Here are highlights from an article Glen Zediker wrote for the Midsouth Blog. In this article Glen focuses on cartridge brass for semi-auto rifles, AR-platform guns in particular. Glen notes that semi-autos are tougher on brass than bolt-action rifles, so you need strong, durable brass, that has been full-length sized. And you need to be careful about neck tension, and primers. The article starts with Glen’s recommendations for tough, hard brass, and then includes the points outlined below.
ONE: Full Length-Size Cases with Adequate Shoulder Set-Back
This is a huge source of debate… amongst my readers, but, since now I’m strictly speaking of semi-auto needs I doubt there will be much dissent: full-length resize all cases! Most cases from most semi-autos will emerge with a pretty well-blown case shoulder [taming down an excessively functioning gas system can reduce this]. Make double-sure you’re sizing the cases down to at least 0.003 clearance. If you don’t there are safety and function problems ahead.
TWO: USE Sufficient Neck Tension
The case neck [must be] reduced an adequate amount to retain the bullet. There should be a minimum net difference of 0.003 inches (three-thousandths) between sized outside case neck diameter and loaded round outside case neck diameter. [Editor — that means at least three thou of “grip”.] Reason: don’t take a chance of inadvertent bullet movement during the recoil and feeding cycles. That movement can be back or forward! It’s easily possible for a bullet to jump ahead when the inertia from the bolt carrier assembly chambers the next round.
THREE: Use Tough Primers
Choose a tough primer! There’s a floating firing pin on an AR15 (M1A also) that is supposed to be held in check but that system doesn’t always work! If you load and extract a round and see a little dimple in the primer, that’s from the firing pin tapping off of it (again, created by inertia of bolt closing). A combination of a high primer and a sensitive primer cup assembly can create a “slam-fire”. Brands? CCI has some mil-spec primers that work well, and I’ve had great success with Remington 7-1/2. Some of the well-respected “match” primers are a little thin. The CCI and Remington also hold up well to the (sometimes) greater firing forces working on the primer (again, from the quick unlocking).
And, finally, make double-sure that each and every primer is seated to below flush with the case head! That’s true for any firearm (because it also means that the primer is fully seated) but imperative for safety in a semi-auto. This is especially an issue for those who use a progressive-type loading press.
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Trigger, Stock Adjustment and Other Features
Stock Cast and Cant Adjustment Procedure
Forum member Danny Reever and this Editor have discussed how novice reloaders can struggle with the fine points of reloading, making errors in seating depth, neck-bushing choice, or sizing their cases. We agreed that a good resource covering more than “Reloading Basics” is sorely needed. Danny reminded me that Glen Zediker’s excellent 
Flash Consistency is very important, shot to shot. The consistency of every component is important: bullet weights, diameters, case wall thicknesses, and all the way down the list. We’re hoping to get more consistent behavior from a “match” or “benchrest” primer, and we’re paying more for it. I can tell you that some brands that aren’t touted as “match” are already consistent. That all comes from experience: try different primers, just respect the need to initially reduce the load for each test.
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There’s More to the Story…
Making Corrections with Limited Sighters
Glen’s books, Handloading For Competition and Top-Grade Ammo, are available at Midsouth 
