December 18th, 2018

Ogives, Meplats, Boat-Tails and Other Bullet Design Elements

Bullet Design Zediker

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

Read Zediker Bullet Design Article | Read Zediker Pressure Signs Article

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.”

Bullet Design Zediker

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.”

Bullet Design Zediker

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:

zediker book glen top grade ammo zediker book glen top grade ammo zediker book glen top grade ammo

All these titles are available from Midsouth Shooters Supply. Click each cover above to purchase from Midsouth.

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November 19th, 2018

Bullet Pointing 101 — How to Point Match Bullet Tips

Berger Bullet Pointing Applied Ballistics Bryan Litz Whidden Pointing Die pointer

Tech Tip by Doc Beech, Applied Ballistics Support Team
I am going to hit on some key points when it comes to bullet pointing. How much pointing and trimming needed is going to depend on the bullet itself. Specifically how bad the bullets are to begin with. Starting out with better-quality projectiles such as Bergers is going to mean two things. First that you don’t need to do as much correction to the meplat, but also that the improvement is going to be less. NOTE: We recommend you DO NOT POINT hunting bullets. Pointing can affect terminal performance in a bad way.

NOTE the change in the bullet tip shape and hollowpoint size after pointing:
Berger Bullet Pointing Applied Ballistics Bryan Litz Whidden Pointing Die pointer

Don’t Over-Point Your Bullets
What is important here is that you never want to over-point. It is far better to be safe, and under-point, rather than over-point and crush the tips even the slightest bit. To quote Bryan Litz exactly: “Best practice is to leave a tiny air gap in the tip so you’re sure not to compress the metal together which will result in crushing. Most of the gain in pointing is taking the bullet tip down to this point. Going a little further doesn’t show on target”. So in essence you are only bringing the tip down a small amount… and you want to make sure you leave an air gap at the tip.

Salazar Whidden Bullet Pointer system

Also keep in mind, bullet pointing is one of those procedures with variable returns. If you only shoot at 100-200 yards, bullet pointing will likely not benefit you. To see the benefits, which can run from 2 to 10% (possibly more with poorly designed bullets), you need be shooting at long range. Bryan says: “Typically, with pointing, you’ll see 3-4% increase in BC on average. If the nose is long and pointy (VLD shape) with a large meplat, that’s where pointing has the biggest effect; up to 8% or 10%. If the meplat is tight on a short tangent nose, the increase can be as small as 1 or 2%.” For example, If you point a Berger .308-caliber 185gr Juggernaut expect to only get a 2% increase in BC.

Berger Bullet Pointing Applied Ballistics Bryan Litz Whidden Pointing Die pointer

Should You Trim after Pointing?
Sometimes you can see tiny imperfections after pointing, but to say you “need” to trim after pointing is to say that the small imperfections make a difference. Bryan Litz advises: “If your goal is to make bullets that fly uniformly at the highest levels, it may not be necessary to trim them.” In fact Bryan states: “I’ve never trimmed a bullet tip, before or after pointing”. So in the end it is up to you to decide.

Pointing is Easy with the Right Tools
The process of pointing in itself is very simple. It takes about as much effort to point bullets as it does to seat bullets. We are simply making the air gap on the tip of the bullet ever-so smaller. Don’t rush the job — go slow. Use smooth and steady pressure on the press when pointing bullets. You don’t want to trap air in the die and damage the bullet tip. You can use most any press, with a caliber-specific sleeve and correct die insert. The Whidden pointing die has a micrometer top so making adjustments is very easy.

Bryan Litz actually helped design the Whidden Bullet Pointing Die System, so you can order the Pointing Die and Inserts directly from Applied Ballistics. Just make sure that you pick up the correct caliber sleeve(s) and appropriate insert(s). As sold by Applied Ballistics, the Whidden Bullet Pointing Die System comes with the die, one tipping insert, and one caliber-specific sleeve. To see which insert(s) you need for your bullet type(s), click this link:

LINK: Whidden Gunworks Pointing Die Insert Selection Chart

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October 28th, 2015

New Hornady ELD Bullets with Heat-Resistant Tips

Hornady ELD Low Drag Heat Resistant Bullet Tip Match Bullets Hunting

In 2016, Hornady will introduce new hunting and match bullets with high-tech, heat resistant tips. Hornady developed the new “Heat Shield” bullet tips after Doppler Radar testing showed that the Ballistic Coefficients (BCs) of old-style tipped bullets were degrading in flight in an unexplained manner. Hornady’s engineers theorized that the old-style plastic bullet tips were deforming in flight due to heat and pressure. Hornady claims this problem occurred with high-BC (0.5+ G1) tipped bullets from a variety of manufacturers. Hornady’s testers believed that, after 150 yards or so, the tips on high-BC bullets were actually melting at the front. That enlarged the meplat, resulting in increased drag.*

Consequently, Hornady developed a new type of bullet tip made from a heat-resistant polymer. Further long-range Doppler Radar testing seemingly confirmed that bullets equipped with the new tips did not suffer from the BC loss previously found. This allowed the bullets to maintain a higher, more consistent BC during the entire trajectory. The end result is a bullet with reduced vertical dispersion at long range (or so Hornady claims).

New Hornady ELD-X Hunting Bullets
For 2016, Hornady will bring out two lines of projectiles using the new tips. The first line of bullets, designed for hunting, will be called ELD-X, standing for “Extreme Low Drag eXpanding”. These feature dark red, translucent, heat-resistant tips. With interlock-style internal construction, these hunting projectiles are designed to yield deep penetration and excellent weight retention. Hornady will offer seven different ELD-X bullet types, ranging in weight from 143 grains (6.5mm) to 220 grains (.30 Cal):

6.5mm, 143 grain (G1 .620 / G7 .310)
7mm, 162 grain (G1 .613 / G7 .308)
7mm, 175 grain (G1 .660 / G7 .330)

.308, 178 grain (G1 .535 / G7 .271)*
.308, 200 grain (G1 .626 / G7 .315)
.308, 212 grain (G1 .673 / G7 .336)
.308, 220 grain (G1 .650 / G7 .325)

NOTE: We don’t know if the stated BC values are based on drag models or actual range testing. These new ELD-X hunting bullets will be loaded into a new line of Precision Hunter Ammo for a variety of popular hunting cartridges.

Hornady ELD Low Drag Heat Resistant Bullet Tip Match Bullets Hunting

New Hornady ELD Match Bullets
Along with its new hunting bullets, Hornady is coming out with a line of ELD Match bullets as well. Hornady’s engineers say the new molded “Heat Shield Tip” should be a boon to competitive shooters: “You can’t point up that copper [tip] as consistently as you can mold a plastic tip. With the ELD Match line, and the Heat Shield Tip technology… we now have a perfected meplat. These bullets allow you to shoot groups with less vertical deviation, or less vertical stringing, because the bullets are exact in their drag [factor].” There are currently four bullets in the ELD Match line:

.264 Caliber (6.5mm), 140 grain (G1 .610 / G7 .305)
.284 Caliber (7mm), 162 grain (G1 .627 / G7 .313)
.308 Caliber (7.62mm), 208 grain (G1 .670 / G7 .335)
.338 Caliber (8.6 mm), 285 grain (G1 .789)

Hornady will offer factory ammunition loaded with ELD Match bullets, starting with 6.5 Creedmoor ammo loaded with the 140gr ELD, and .338 Lapua Magnum ammo loaded with the 285gr ELD.

Better Tips Make a Difference — But other Factors Are Important
Hornady claims that its new Heat Shield Tips are more uniform than the meplats on conventional jacketed, hollow-point bullets. This, Hornady says, should provide greater bullet-to-bullet BC consistency than is possible with conventional, non-tipped bullets.

We have heard such claims before. Plastic tips are good, so long as they are inserted perfectly in the bullet. But sometimes they are crooked (off-axis) — we’ve seen that with various brands of tipped projectiles. Other factors will affect bullet performance as well, such as bullet weight, bullet diameter, and bullet bearing surface length. Even with perfectly uniform bullet tips, if bullet weights or diameters are inconsistent across a sample, you can still have accuracy issues (and pressure-related velocity variances). Likewise, if the bearing surface lengths vary considerably from one bullet to the next, this can increase velocity spread and otherwise have a deleterious effect on accuracy.

So, overall, we think Hornady has probably engineered a better bullet tip, which is a good thing. On the other hand there are many other factors (beyond tip uniformity) involved in long-range bullet performance. It will be interesting to test the new ELD Match bullets to see how they compare with the best hollow point jacketed bullets from other manufacturers.

MORE TECHNICAL DETAILS

* Hornady’s Chief Ballistician Dave Emary authored a technical report based on the Doppler Radar testing of a variety of tipped Bullets. CLICK HERE for Emary Report. Here are some of the report’s key observations and conclusions:

After early testing of prototype bullets it was observed that all currently manufactured tipped projectiles’ drag curves were convex, not concave and that abnormally low ballistic coefficients were being observed over long ranges. The drag was rapidly increasing at high velocities.

At this point extensive testing was done with all types of commercially-available tipped projectiles. They all exhibited this behavior to a greater or lesser extent depending on their ballistic coefficient and launch velocity. Most projectiles exhibited BCs relatively close to published values for 150 to 200 yards of flight. Beyond these distances they all showed BCs substantially below published values.

It was obvious that something was changing in the tipped projectiles to cause a rapid increase in drag at higher velocities. The drag increases were most noticeable from 100 to about 500 yards. Drag increases stopped at velocities below approximately 2,100 fps. This behavior was not observed with hollow point or exposed lead (spitzer) style designs. The problem magnified as the velocity was increased. The problem was worse for heavier, higher-BC projectiles that maintained higher velocities longer. After some consideration the answer was obvious and one that several people had wondered about for some time but had no way to prove their thoughts.

The tip of a bullet at 3,000 fps will see temperatures as high as 850 degrees F and decreasing as
the bullet slows down. These temperatures on the tip were a known fact. What wasn’t known was how long it would take at these peak and decreasing temperatures for the polymer tips to begin showing effects, if at all. As it turns out it is within the first 100 yards of flight. Currently-used polymers in projectile tips begin to have properties like rubber at approximately -65 to 50 degrees F and will melt at 300 to 350 degrees F, depending on the exact polymer.

All current polymer-tipped projectiles have tips that are at best softening and deforming in flight and under many circumstances melting and badly deforming. To cut through a lot of technical discussion the problem becomes worse at higher ambient air temperatures (summer) and higher launch velocities. Projectiles that have a high BC and retain velocity well see higher stagnation temperatures for longer lengths of time and have greater degradation of the tip. Simply put it is a heat capacity problem –temperature times time. This makes BCs for current tipped projectiles a rough average over some distance, dependent on atmospheric conditions and muzzle velocity, and does not allow the accurate prediction of downrange ballistics much beyond 400 yards.

Permalink Bullets, Brass, Ammo, New Product 10 Comments »
January 13th, 2015

Using the Giraud Power Trimmer — Smart Video from Erik Cortina

Forum member Erik Cortina recently launched his own YouTube Channel dedicated to precision reloading and accurizing. Erik’s videos demonstrate the proper use of specialized reloading tools and provide helpful hints. Erik’s latest video is about the “mother of all brass trimmers”, the Giraud powered case trimmer. Erik says: “It you do volume reloading… this is the only trimmer to get. It not only trims to length but it also chamfers your case mouth inside and out.” In his video, Erik offers some very clever and useful tips that will help you get the most from your Giraud.

The Giraud trimmer is very precise. When set up correctly, it can trim brass with amazing consistency. In the video, Erik trims 5 pieces of brass in 15 seconds (6:32 mark). He then measures all five with precision calipers (7:00-8:08). All lengths are exact within .0005 (half a thousandth). Erik notes that the Giraud trimmer indexes off the case shoulder. As long as you have fire-formed brass with consistent base-to-shoulder dimensions, you should get very consistent trim lengths.

The secret to the system is a 3-way cutting head. This cutter can be swapped in and out in a couple minutes with wrenches provided with the kit. Erik has three different heads; one each for 6.5mm, 7mm, and .30 caliber. The video shows how to adjust the cutting heads to match caliber diameter (and to get the desired amount of inside/outside chamfer).

This is a manufacturer’s photo showing an older model.
Erik Cortina Meplat Giraud Case Trimmer YouTube Video Lapua

To trim and chamfer cases, you simply insert them nose-first into the cartridge-specific case-holder. Erick offers a smart tip — He uses a die locking ring to position the cartridge holder (3:15). This can be locked in place. Erik says die locking rings work much better than the hex-nuts provided by Giraud (with the hex-nut, one must re-set cut length each time you change case-holders.)

Erik Cortina Meplat Giraud Case Trimmer YouTube Video Lapua

The Giraud can be used in either horizontal or vertical modes. Erik prefers to have the trimmer aligned vertically, allowing him to push cases down on the trimmer head. But the trimming unit has twin sets of rubber feet, allowing horizontal or vertical orientation.

Erik Cortina Meplat Giraud Case Trimmer YouTube Video Lapua

Improved Case-Holder Made with Chamber Reamer:
For his .284 Shehane, Erik had to create his own case-holder (Giraud does not make one for that wildcat cartridge). Erik used his chamber reamer. To his surprise, Erik found that the brass was easier to trim in the custom case holder (compared to the Giraud-made spring-loaded holders). With a perfect fit, trimming and case extraction went more smoothly and the process was easier on his hands. (See 9:00-10:00). Based on Erik’s experience, you may want to create your own custom case-holder.

Trim Bullet Meplats Also
With a special bullet-holder fitting and meplat cutter head, the Giraud power trimmer can be used to trim bullet meplats. Trimming meplats can help make the Ballistic Coefficents of a batch of bullets more consistent. Uniforming meplats is also often done as a first step in the process of “tipping” bullets to improve BC.

Erik Cortina Meplat Giraud Case Trimmer YouTube Video Lapua

Giraud Power Trimmer

Permalink - Videos, Reloading, Tech Tip 8 Comments »
November 14th, 2014

Whidden Gunworks Bullet Pointing Die System

Gear Review by GS Arizona

This article originally appeared in the Rifleman’s Journal website.
Many of you have doubtlessly read Bryan Litz’s articles in our Daily Bulletin 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.

Whidden Bullet pointer tool

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.

Whidden Bullet pointer tool

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.

Whidden Pointing dieIt 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 $220.00 (with one insert). Additional die inserts are $42.00 each. Extra caliber sleeves are also $42.00. You can purchase directly from Whidden Gunworks, or from Sinclair International.

Whidden Bullet pointer tool

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October 11th, 2011

New Berger 105gr 6mm Hybrid Bullets Perform Well

105gr Hybrid Tests Demonstrate Excellent Accuracy and Consistency
By Robert Whitley
After the initial Daily Bulletin Report on the new Berger 6mm 105gr Hybrids, I did some accuracy and consistency field testing with these new bullets. They shot so well, I thought an update was in order. My 100-yard testing has revealed much about these new bullets — all of it good so far. The test rifle was a MAK Tube Gun with a trued Rem 700 action (glued in), with a 6mm Brux 30″, 1:8″-twist barrel chambered with a no-neck-turn 6mm BRX chamber (1.563″ max case and .120″ free bore). The 6mm 105gr Hybrids fit and work well in this 6 BRX chamber configuration. (CLICK HERE to view a print of the reamer I used for the 6 BRX chamber.)

Berger 6mm 105 grain Hybrid bullet

Hybrids Show Excellent Accuracy in Prone Tests (with Sling)
As some may know, I am predominantly a prone shooter and do most of my load testing prone with a sling. I chose to do the same with these Hybrids, to see how they would perform when fired as they would be in a prone match. In this case, shooting prone with sling, I shot four 10-shot groups (two 10-shot groups in each of two range session). All four groups were right around .5 MOA (i.e. each group about .750″ edge-to-edge, minus a bullet diameter of .243″ = .507″). The new Berger 6mm 105gr Hybrid bullets had no problems doing this. The groups shot were also consistent with the best groups I have been able to shoot in the past with the Berger 108gr BT bullets and the Berger 105gr VLD bullets, and I consider both of those bullets to be excellent and accurate. There is no question in my mind that these new Hybrid bullets are accurate, and the consistency is there! Check out my test targets below.

The two 10-shot targets above were shot at 100 yards on September 30th, prone with sling. The 6 BRX load was: Berger 6mm 105gr Hybrids, Lapua brass, 32.0 grains N140, Federal 205M-AR primers, .020″ jump. Note: If you put the targets over each other the groups line up perfectly.

These two 10-shot targets (above) were shot at 100 yards on September 23, prone with sling. The 6 BRX load was: Berger 6mm 105gr Hybrids, Lapua brass, 31.0 grains H4895, Federal 205M-AR primers, .020″ jump. When I can shoot 20 Xs in a row (as I did with these two targets) the rifle is really shooting well.

Accuracy needs to be coupled with consistency, especially when running longer strings of fire or in matches demanding a larger number of hits on the target. I am pleased to report that I have found the Berger 105gr Hybrid bullets to be consistently accurate bullets (i.e. there were no anomalies or fliers, they just keep going where you pointed the rifle). At each of the last two range sessions I shot back to back 10-shot groups with no break between the two (i.e. 20 shots in a row and only switching to the next target after 10 shots). Not only did the individual 10-shot groups stay tight, but if you hold each first target over the second target, the groups are right on top of one another. This is what I look for in terms of consistency — that I can keep shooting, and the bullets keep going right into the group, with no odd fliers.

105gr Hybrid Bearing Surface and Optimum Free Bore
Shooters may wonder how the new 6mm 105gr Hybrids function with the existing freebores on chambers set up for current Berger 105gr VLDs and Berger 108gr BT bullets. Based on the investigation and measuring of various chambers, here are some general guidelines:

1. For a chamber with a 1.5° throat angle, and the bullets touching the lands, the Berger 105gr Hybrid bullets sit up in the neck a little further than both the current production Berger 105 VLD Target bullets and the Berger 108gr BT bullets.

2. Based on basic measuring and testing, for the junction of the boat tail and bearing surface of a 6mm 105gr Hybrid bullet to be in the same spot as other bullets, the 105 Hybrid (Lot #3079) would need about .020″ – .025″ less freebore than recent production Berger 105gr Target VLD bullets (Lot #3220) and about .030″ – .035″ less freebore than recent Berger 108gr Target BT bullets (lot #2791).

3. Since the Hybrids are designed to work both in the lands and jumped away from the lands, some extra freebore may not be a bad thing. In truth, the 105 Hybrid bullets should work well and fit well in various 6mm chamberings (such as 6 BRX, 6 Dasher, 6mmAR etc.) which have been optimized for the previous generation, non-Hybrid 6mm Berger 105s and 108s.

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