May 5th, 2017

Bullet Concentricity Basics — What You Need to Know

Sinclair concentricity 101 eccentricity run-out reloading plans

Sinclair International reloading toolsSinclair International has released an interesting article about Case Concentricity* and bullet “run-out”. This instructional article by Bob Kohl explains the reasons brass can exhibit poor concentricity, and why high bullet run-out can be detrimental to accuracy.

Concentricity, Bullet Alignment, and Accuracy by Bob Kohl
The purpose of loading your own ammo is to minimize all the variables that can affect accuracy and can be controlled with proper and conscientious handloading. Concentricity and bullet run-out are important when you’re loading for accuracy. Ideally, it’s important to strive to make each round the same as the one before it and the one after it. It’s a simple issue of uniformity.

The reason shooters work with tools and gauges to measure and control concentricity is simple: to make sure the bullet starts down the bore consistently in line with the bore. If the case isn’t properly concentric and the bullet isn’t properly aligned down the center of the bore, the bullet will enter the rifling inconsistently. While the bore might force the bullet to align itself with the bore (but normally it doesn’t), the bullet may be damaged or overstressed in the process – if it even it corrects itself in transit. These are issues we strive to remedy by handloading, to maintain the best standard possible for accurate ammunition.

The term “concentricity” is derived from “concentric circle”. In simple terms it’s the issue of having the outside of the cartridge in a concentric circle around the center. That goes from case head and center of the flash hole, to the tip of the bullet.

Factors Affecting Concentricity

The point of using this term is to identify a series of issues that affect accurate ammunition. Ideally this would work best with a straight-walled case; but since most rifle cartridge cases are tapered, it equates to the smallest cross section that can be measured point by point to verify the concentric circle around the center. For the examples below, I’m working with .308 Winchester ammo.

Concentricity run-out cartridge case
Figure 1: The cartridge.

Concentricity run-out cartridge case
Figure 2: Centerline axis of the case, extending from flash hole to case mouth.

The case walls have to be in perfect alignment with the center, or axis, of that case, even if it’s measured at a thousandth of an inch per segment (in a tapered case).

Concentricity run-out cartridge case
Figure 3: Case body in alignment with its axis, or centerline, even in a tapered case.

The case neck must also be in alignment with its axis. By not doing so you can have erratic bullet entry into the bore. The case neck wall itself should be as uniform as possible in alignment and in thickness (see the M80 7.62x51mm NATO cartridge in Figure 5) and brass can change its alignment and shape. It’s why we expand the case neck or while some folks ream the inside of the neck and then turn the outside for consistent thickness, which affects the tension on the bullet when seated.

Concentricity run-out cartridge case
Figure 4: Neck in alignment with center of the case axis.

Concentricity run-out cartridge case
Figure 5: Variations in case neck wall thickness, especially on some military brass, can cause an offset of the bullet in its alignment. This is an M80 ball round. Note the distinct difference of the neck walls.

Having a ball micrometer on hand helps, especially with military brass like 7.62x51mm in a semi-auto rifle, where there are limits as to how thin you want the neck walls to be. In the case of 7.62 ball brass you want to keep the wall to .0145″.

Concentricity run-out cartridge case
Figure 6: A ball micrometer like this RCBS tool (#100-010-268) can measure case neck thickness.

Turning the outside of the neck wall is important with .308 military cases regardless of whether you expand or ream the neck walls. There are several outside neck turning tools from Forster, Hornady, Sinclair, and others. I’ve been using classic Forster case trimming (#100-203-301) and neck turning (#749-012-890) tools for 40 years.

Bullet Run-Out
The cartridge, after being loaded, still needs to be in alignment with the center of the case axis. Figure 7 shows a bad example of this, a round of M80 ball. A tilted bullet is measured for what’s known as bullet “run-out”.

Concentricity run-out cartridge case
Figure 7: An M80 round with the bullet tilted and not aligned with the axis. This will be a flyer!

Run-out can be affected by several things: (1) improperly indexing your case while sizing, which includes not using the proper shell holder, especially while using a normal expander ball on the sizing die (it also can stretch the brass). (2) The head of a turret press can flex; and (3) improper or sloppy bullet seating. This is also relevant when it comes to using a progressive press when trying to load accuracy ammo.

Mid Tompkins came up with a simple solution for better bullet seating years ago. Seat your bullet half way into the case, back off the seater die and rotate the case 180 degrees before you finish seating the bullet. It cuts down on run-out problems, especially with military brass. You also want to gently ream the inside of the neck mouth to keep from having any brass mar the surface of the bullet jacket and make proper seating easier. A tilted bullet often means a flyer.

Concentricity run-out cartridge case
Figure 8: Proper alignment from the center of the case head to the tip of the bullet.

CLICK HERE to READ FULL ARTICLE With More Photos and Tips


*Actually some folks would say that if we are talking about things being off-center or out-of-round, we are actually talking about “eccentricity”. But the tools we use are called “Concentricity Gauges” and Concentricity is the term most commonly used when discussing this subject.

Story Tip from EdLongrange. We welcome reader submissions.
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April 23rd, 2017

Polish Inside of Seating Stems to Avoid Ring Marks on Bullets

Seating Stem Reloading Tip Sierra Bullet .223 Remington compressed loads

Here’s a helpful hint for hand-loaders from Sierra Bullets. While this article focuses on Sierra’s new Tipped Match-King bullets, the recommended solutions apply to other bullet types as well. The article explains how sharp edges on a seating stem can cause a ring to be pressed into the bullet jacket — especially with compressed loads that resist downward bullet movement. Here Sierra technician Rich Machholz diagnoses the problem and provides a solution.

Seating Stem Reloading Tip Sierra Bullet .223 Remington compressed loads

Solutions for Ring Marks Caused by Seating Stems

by Sierra Bullets Ballistic Technician Rich Machholz
Now that the new Tipped MatchKing® (TMK) bullets are being shipped and shooters are putting them to use I have received several calls regarding marking on the bullet ogive from the seating stem.

The cause can be traced to one of several things. In the .223 and especially with the long, 77 grain TMK seated at 2.250” or even 2.260” most loads of Varget® and Reloder® 15 are compressed loads, sometimes heavily compressed. This puts a great deal of pressure on the bullet through the seating stem. The result of all this pressure is a mark of varying depth and appearance on the ogive of the bullet. [Editor: We have seen this issue with a variety of other bullet types/shapes as well, including non-tipped VLDs. The solution is profiling the internal cone of the seating stem to match your bullet shape.]

Some older seating stems might even bear against the tip of the bullet which can make a slight bulge in the jacket just below the junction of the resin tip and the copper jacket in a compressed load. If this is the case there is not a ready fix other than calling the die manufacturer and requesting a new deeper seating stem.

Polish Your Seating Stem to Remove Sharp Internal Edges
If the seating stem is of proper depth the culprit most generally is a thin sharp edge on the inside taper of the seating stem. This is an easy fix that can be accomplished by chucking a spare 77 grain bullet in your drill, coating it with valve grinding compound or even rubbing compound or in a pinch even tooth paste.* Remove the seating stem assembly from the seating die. Turn the drill on and put the seating stem recess over the spinning bullet with the polishing compound to break or smooth the sharp edge that is making the offending mark. This might take more than one application to get the proper polish depending upon what you use, but the more you polish the better the blend of angles which will [ensure the stem matches the bullet contours, not leaving a sharp ring].

If the above is a little more than you care to tackle you might try very fine emery cloth twisted to a point that can be inserted into the mouth to the seating stem and rotated to polish the inside to eliminate any sharp edges that might be present.

Load Advice for 77gr TMKs in the .223 Rem
And last but certainly not least. Actually, even though we don’t say you need additional data for the TMKs, remember you are dealing with heavily-compressed loads in some cases because of the additional bullet length. Due to the additional length of these new bullets and in the interest of gaining some room in the case you might consider trying a slightly faster extruded powder like BenchMark or the 4895s or an even more dense powder like the spherical H335®, CFE223 or TAC. The extra room will allow for trouble free bullet seating also.

Good luck and remember we are no further away than your telephone: 1-800-223-8799.

Sierra Bullets Match-King Reloading Bullet Seating

Permalink Bullets, Brass, Ammo, Tech Tip 2 Comments »
February 24th, 2017

How “Gun Smart” Are You? Take the Shoot 101 Test…

Shoot 101 Quiz
How much of an expert are you when it comes to firearms and ballistics? Test your knowledge with this interactive test. Vista Outdoors (formerly ATK Sporting Group) has launched a new multi-platform media campaign called Shoot 101, which provides “how to” information about shooting, optics, and outdoor gear.

On the Shoot 101 website, you’ll find a Ballistics Quiz. The questions are pretty basic, but it’s still fun to see if you get all the answers correct.

You don’t need a lot of technical knowledge. Roughly a third of the questions are about projectile types and bullet construction. Note, for some reason the layout doesn’t show all the possible answers at first. So, for each question, be sure to scroll down using the blue scroll bar on the right.

CLICK HERE to Go to Ballistics QUIZ Page

Sample Ballistics Question

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February 15th, 2017

P-Dog Gone Good Deal on Varmint Bullets

CFE 223 Powder Varmint Bullet Prairie dog
This custom war wagon hauls varmint hunters around the Longmeadow Game Resort in Colorado.

If you’re planning a spring Prairie Dog adventure, it’s time to load up a big supply of ammo. On a 4-day varmint safari you can easily shoot 800 rounds or more in a prime P-Dog location. To save on ammo costs for high-volume shooting, it makes sense to buy components in bulk. Here’s a super deal on bullets for your .224-caliber varmint rig.

Right now Midsouth Shooters’ Supply is running a special on Varmint Nightmare XTreme Bullets. Available in both hollow point (HP) and lead-tip soft point (SP) styles, you can get these bullets for under $50.00 for 500. The .224 55gr Flat Base Soft Point variety is on sale this week for just $42.92 for 500 bullets (that works out to just $8.58 per hundred). We’ve loaded these in .223 Rem, 22 Dasher, and 22-250 cartridges and they worked well (considering the really low price).

CFE 223 Powder Varmint Bullet Prairie dog

For shorter-range ground squirrel loads, we also like the .224 34gr Flat Base Hollow Point at $44.25/500. These work great in a .221 Fireball (using Lapua .221 Fireball brass of course).

Powder Suggestion for High-Volume Varmint Loads
For high-shot-count varmint safaris, you want a clean-burning powder that minimizes barrel fouling. While there are many great powders for the .223 Rem, we like Hodgdon CFE 223 for our high-volume varmint loads. This powder really seems to keep barrels cleaner. Originally developed for U.S. rapid-fire military systems, CFE 223 incorporates a proprietary chemistry named “Copper Fouling Eraser”. Based on tests with extended shot strings, Hodgdon claims that, by using CFE™223, match shooters, varmint hunters, and AR shooters can maintain accuracy for longer periods, with less barrel-cleaning time. You may want to check it out.

CFE 223 Powder Varmint Bullet Prairie dog

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February 14th, 2017

Blast from the Past — Video Shows Ricochet Danger

This an older video from the YouTube archives but we expect many readers have still not seen it yet. It definitely teaches an important lesson — never underestimate the destructive power of rifle-launched projectiles. What appears a “safe distance” from steel may actually be well within the danger zone.

YouTube Preview Image

In this video a rather ignorant (yet lucky) fellow demonstrates what NOT to do with a large-caliber rifle (a 50 BMG apparently). He shoots at a steel target about 70 yards away and a bullet fragment comes back directly at him. He was lucky enough that the ricochet just smacked his left ear muff. Another inch to the right and he could have lost his eye… or worse.

If you have ever done much action pistol shooting at close range on steel targets, you’ll know about the hazards of ricochets and bullet splashback. That’s why you should only shoot low-velocity rounds with soft lead or frangible bullets when shooting at relatively close range.

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January 25th, 2017

22 Nosler — More Details, Load Data — And a Bit of History

22 Nolser .220 Thunderbolt 224 winchester E5 experimental 22-250

At SHOT Show 2017, Nosler showcased a new .22-caliber cartridge designed for AR-platform rifles. Called the 22 Nosler, the new cartridge resembles a 6.8 SPC necked down to .22 caliber. Comparing Nosler’s ammo specs with Hodgdon load data, it looks like the 22 Nosler can deliver about 250-300 fps more velocity than the standard .223 Rem cartridge. That’s significant for varminters looking for higher performance from an AR15-type rifle. With a 55-grain bullet, highest possible velocity is 3500+ fps with a max load of Hodgdon CFE 223 powder, based on this Nosler Load Chart:

22 Nolser .220 Thunderbolt 224 winchester E5 experimental 22-250

MORE LOAD DATA for 22 Nosler (Click tabs after jump)

22 Nosler LOAD PDFs:
https://load-data.nosler.com/nosler-load-data/pdf/22-nosler/22-nosler-55gr.pdf
https://load-data.nosler.com/nosler-load-data/pdf/22-nosler/22-nosler-64gr.pdf
https://load-data.nosler.com/nosler-load-data/pdf/22-nosler/22-nosler-69gr-70gr.pdf
https://load-data.nosler.com/nosler-load-data/pdf/22-nosler/22-nosler-77gr.pdf

Nosler will produce 22 Nosler ammunition in various bullet weights, starting with 55 grain and 77 grain. To run the 22 Nosler, an AR owner will need a new upper and 6.8 SPC type magazines. This video explains how to convert your AR-platform rifle to run the 22 Nosler.

“Everything Old Is New Again…”

Examining the 22 Nosler cartridge, our friend Grant Ubl had a case of “deja vu”. He thinks the new 22 Nosler bears a striking resemblance to a wildcat from the 1960s: “The .22 Nosler looks like a throwback to the 1963-vintage .224 Winchester E5 experimental cartridge, right down to the rebated rim.” Here is an old Winchester print:

Another poster said this cartridge resembles the “.220 Thunderbolt” a wildcat devised by John Scandale in 2004. Posting on Facebook, Mr. Scandale said the designs were very similar. According to Keystone Accuracy, the .220 Thunderbolt’s “design origin came from the now largely popular 6mm Hagar in its infancy stage back in 2003.” While it looks very similar to a 6.8 SPC necked to .224, the .220 Thunderbolt is different because the 6mm Hagar brass is 0.100″ longer than 6.8 SPC. Read History of .220 Thunderbolt.

Neck-up the 22 Nosler to .25 Caliber?

Dan Z. has inspected in the 22 Nosler ammunition and he’d like to see a .25 Caliber version. On Facebook, Dan posted: “I got my hands on some of the ammo a couple weeks ago. It does look like a .223 that has its body diameter expanded to that of a 6.8. Consequently, it is longer than the 6.8 overall and in the body. I necked a piece of fired brass to 6.8 and it looked like it would provide some improvement in velocity. A more interesting idea might be to neck it to .25 as a .250 Savage performance clone in an AR-15 platform.”

Permalink Bullets, Brass, Ammo, Hunting/Varminting, New Product 8 Comments »
January 3rd, 2017

How to Spot Trace — The Bullet’s Wake Signature

NSSF long range shooting bullet trace spotting scopeHave you ever seen bullet trace? Do you know how to read trace? Well watch this NSSF video to learn how to recognize trace, and use trace to help adjust your aim on the target. Watch the video from 1:50 to 2:20 to see trace in slow motion. Watch carefully starting and you can see the trace in the milli-seconds before the bullet hits the target.

Rod Ryan of Storm Mountain Training Center explains how to read bullet trace: “If you’re looking through your spotting scope, and you focus on your target, and then back off about a quarter-turn counter-clockwise (in most cases) you’ll be able to focus a little closer to you and you’ll actually see this movement of air — it’s called the trace — going down range.”

Watch the Slow-Mo Trace Starting at 1:50. From 2:10 to 2:20 you can actually see the bullet hanging in the air just before it hits the target.

Trace is easier to see when there’s some moisture in the air. By following the bullet trace you can see if you shot is running high or low, left or right, even if you can’t see a shot imparct on the target. This is important, particularly when you’re attempting an steep-angled shot and it’s hard to see bullet impact on the ground near the target. Rod Ryan explains: “A lot of times we have an angular hill-top and you’re shooting directly into a [steep] drop [so] you can’t see any splash at all or any dirt flow after the miss happens. In this case the last thing you see is that trace.”

What you’re seeing is akin to the wake that forms behind a motorboat, but it is a trail of disturbed air rather than disturbed water. Ryan says: “It’s just like you’re looking down from space at a motorboat in the water, you can see that wake. Very close to the target, you can actually see it roll in… if you’re taking a shot at say… four, five, six hundred yards, it’s very prevalent, you can see it very well.”

Video find by EdLongrange. We welcome reader submissions.
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December 30th, 2016

Ballistics Linguistics: Bullet “Caliber of Ogive” Defined

Sierra Caliber of Ogive Bullet Sierra BC geometry

This article, which originally appeared in the Sierra Bullets Blog, provides a new terminology that helps describe the geometry of bullets. Once you understand the meaning of “Caliber(s) of Ogive”, you can quickly evaluate potential bullet performance by comparing listed Caliber of Ogive numeric values.

by Mark Walker, Sierra Bullets New Product Development Manager
During one of our recent product releases, we listed the “caliber of ogive” of the bullet in the product description. While some understood what that number meant, it appears that some are not aware of what the number is and why it is important. In a nutshell, the “caliber of ogive” number will tell you how sleek the front end of the bullet is. The higher the number is, the sleeker the bullet. It also makes it easy to compare the ogives of different caliber bullets. If you want to know if a certain .308 caliber bullet is sleeker than a 7mm bullet, simply compare their “caliber of ogive” numbers.

So exactly how do you figure “caliber of ogive”? If you look at the drawing of the .30 caliber 175 gr HPBT bullet #2275 (at top), you will see that the actual radius of the ogive is 2.240. If you take that 2.240 ogive radius and divide by the diameter (or caliber) of the bullet you would get 7.27 “calibers of ogive” (2.240 ÷ .308 = 7.27). (See top photo).

In a nutshell, the “caliber of ogive” number will tell you how sleek the front end of the bullet is. The higher the number is, the sleeker the bullet.

Next let’s look at the print (below) of our 6.5mm 142gr HPBT #1742 bullet for comparison. The actual radius of the ogive is 2.756. Like with the .30 caliber 175 gr HPBT bullet #2275, if you divide 2.756 by the diameter (or caliber) of the bullet you get 10.44 “calibers of ogive”.

Sierra Caliber of Ogive Bullet Sierra BC geometry

As most people know, it has been determined through testing that the 6.5mm 142gr HPBT #1742 has a significantly higher ballistic coefficient than the .30 caliber 175 gr HPBT bullet #2275. However by simply comparing the “caliber of ogive” number of each bullet you can easily see that the 6.5mm 142 gr HPBT #1742 is significantly sleeker than the .30 caliber 175 gr HPBT bullet #2275 even without firing a shot.

Some people would say why not just compare the actual ogive radius dimensions instead of using the “caliber of ogive” figure. If we were comparing only bullets of the exact same diameter, then that would be a reasonable thought process. However, that idea falls apart when you start trying to compare the ogives of bullets of different diameters. As you can see with the two bullets presented above, if we compare the actual ogive radius dimensions of both bullets the difference is not much at all.

However, once again, testing has shown that the 6.5mm 142 gr HPBT #1742 has a significantly higher BC. The only way that this significant increase shows up, other than when we fire the bullets in testing, is by comparing the “caliber of ogive” measurement from both bullets.

Hopefully this will help explain what we mean when we talk about “caliber of ogive” and why it’s a handy number to use when comparing bullets. This information will help you to make an informed decision the next time you are in the market to buy bullets.

Sierra Bullets Caliber of Ogive Bullet BC SMK

Story tip from Grant Ubl. We welcome reader submissions.
Permalink Bullets, Brass, Ammo, Reloading 2 Comments »
September 18th, 2016

CGI Magic — 3D Animation of Pistol Rounds Being Fired

GECO Ruag Ammotec RWS ammo 3D animation video

Here’s a very cool 3D Animation showing pistol rounds being fired. Computer-generated graphics provide a look inside the cartridge at the moment of ignition as the primer fires and the flame front moves through the ignited powder. It’s really kind of mesmerizing. If you’ve every wondered just what happens inside your cartridges the moment that firing pin strikes, then watch this video…

Watch Video to See Handgun Ammo Being Chambered and Fired:

GECO Ruag Ammotec RWS ammo 3D animation videoThis animated video from German ammo-maker GECO (part of the Swiss RUAG group of companies) reveals the inside of a pistol cartridge, showing jacket, lead core, case, powder and primer. Employing advanced 3D rendering and computer graphics, the video shows an X-ray view of ammo being loaded in a handgun, feeding from a magazine.

Then it really gets interesting. At 1:32 – 1:50 you’ll see the firing pin strike the primer cup, the primer’s hot jet streaming through the flash-hole, and the powder igniting. Finally you can see the bullet as it moves down the barrel and spins its way to a target. This is a very nicely-produced video. If you’ve ever wondered what happens inside a cartridge when you pull the trigger, this video shows all. They say “a picture’s worth a thousand words”… well a 3D video is even better.

GECO Ruag Ammotec RWS ammo 3D animation video

GECO Ruag Ammotec RWS ammo 3D animation video

GECO Ruag Ammotec RWS ammo 3D animation video

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August 23rd, 2016

Reloading Tip: Bullet Bearing Surface and Pressure

USAMU Bullet Ogive Comparision Safety Reloading
Photo 1: Three Near-Equal-Weight 7mm Bullets with Different Shapes

TECH TIP: Bullets of the same weight (and caliber) can generate very different pressure levels due to variances in Bearing Surface Length (BSL).

Bullet 1 (L-R), the RN/FB, has a very slight taper and only reaches its full diameter (0.284″) very near the cannelure. This taper is often seen on similar bullets — it helps reduce pressures with good accuracy. The calculated BSL of Bullet 1 was ~0.324″. The BSL of Bullet 2, in the center, was ~0.430”, and Bullet 3’s was ~ 0.463″. Obviously, bullets can be visually deceiving as to BSL!


This article from the USAMU covers an important safety issue — why you should never assume that a “book” load for a particular bullet will be safe with an equal-weight bullet of different shape/design. The shape and bearing surface of the bullet will affect the pressure generated inside the barrel. This is part of the USAMU’s Handloading Hump Day series, publiches on the USAMU Facebook page.

Beginning Handloading, Part 13:
Extrapolating Beyond Your Data, or … “I Don’t Know, What I Don’t Know!”

We continue our Handloading Safety theme, focusing on not inadvertently exceeding the boundaries of known, safe data. Bullet manufacturers’ loading manuals often display three, four, or more similar-weight bullets grouped together with one set of load recipes. The manufacturer has tested these bullets and developed safe data for that group. However, seeing data in this format can tempt loaders — especially new ones — to think that ALL bullets of a given weight and caliber can interchangeably use the same load data. Actually, not so much.

The researchers ensure their data is safe with the bullet yielding the highest pressure. Thus, all others in that group should produce equal or less pressure, and they are safe using this data.

However, bullet designs include many variables such as different bearing surface lengths, hardness, and even slight variations in diameter. These can occasionally range up to 0.001″ by design. Thus, choosing untested bullets of the same weight and caliber, and using them with data not developed for them can yield excess pressures.

This is only one of the countless reasons not to begin at or very near the highest pressure loads during load development. Always begin at the starting load and look for pressure signs as one increases powder charges.

Bullet bearing surface length (BSL) is often overlooked when considering maximum safe powder charges and pressures. In photo 1 (at top), note the differences in the bullets’ appearance. All three are 7mm, and their maximum weight difference is just five grains. Yet, the traditional round nose, flat base design on the left appears to have much more BSL than the sleeker match bullets. All things being equal, based on appearance, the RN/FB bullet seems likely to reach maximum pressure with significantly less powder than the other two designs.

Bearing Surface Measurement Considerations
Some might be tempted to use a bullet ogive comparator (or two) to measure bullets’ true BSL for comparison’s sake. Unfortunately, comparators don’t typically measure maximum bullet diameter and this approach can be deceiving.

Photo 2: The Perils of Measuring Bearing Surface Length with Comparators
USAMU Bullet Ogive Comparision Safety Reloading

In Photo 2, two 7mm comparators have been installed on a dial caliper in an attempt to measure BSL. Using this approach, the BSLs differed sharply from the original [measurements]. The comparator-measured Bullet 1 BSL was 0.694” vs. 0.324” (original), Bullet 2 was 0.601” (comparator) vs. 0.430” (original), and Bullet 3 (shown in Photo 2) was 0.602” (comparator) vs. 0.463” (original). [Editor’s comment — Note the very large difference for Bullet 1, masking the fact that the true full diameter on this bullet starts very far back.]

Permalink Bullets, Brass, Ammo, Reloading 2 Comments »
August 1st, 2016

How Rifle Ammunition Works — Amazing CGI Animation

What happens inside a rifle chamber and barrel when a cartridge fires can’t be seen by the naked eye (unless you are a Super-Hero with X-Ray vision). But now, with the help of 3D-style computer animation, you can see every stage in the process of a rifle round being fired.

3D animation bullet ammunition in rifle

In this amazing video, X-Ray-style 3D animation illustrates the primer igniting, the propellant burning, and the bullet moving through the barrel. The video then shows how the bullet spins as it flies along its trajectory. Finally, this animation shows the bullet impacting ballistic gelatin. Watch the bullet mushroom and deform as it creates a “wound channel” in the gelatin. This excellent video was commissioned by Czech ammo-maker Sellier & Bellot to demonstrate its hunting ammunition. The design, 3D rendering, and animation was done by Grafické studio VLADO.

Watch Video – Cartridge Ignition Sequence Starts at 1:45 Time-Mark

Video find by Seb Lambang. We welcome reader submissions.
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June 18th, 2016

Sierra MatchKing (SMK) vs. Sierra Tipped MatchKing (TMK)

Sierra Tipped MatchKing bullet TMK SMK Tommy Todd

by Sierra Bullets Chief Ballistician Tommy Todd

Since Sierra introduced the Tipped MatchKing® (TMK®) line of bullets in 2015, we have had a few questions from customers regarding the two lines of bullets (MK vs TMK). Some shooters are concerned that the tried-and-true MatchKing® bullets will be replaced with the Tipped MatchKing® bullets. For those of you worried, relax, the old standby MatchKings® that you have shot for years are here to stay, and we will happily continue to make them for you.

Sierra Tipped MatchKing bullet TMK SMK Tommy Todd

For those that like to try new products, we are planning on both continuing and expanding the Tipped MatchKing® line. Even where there are two bullets within these two lines that have matching weights (pictured above), 22 caliber 69 and 77 grain, 6mm 95 gr, 30 caliber 125, 155, 168 and 175 grains, we are not going to replace the MatchKings® with the Tipped MatchKing®. We are, however, going to continue to offer both lines of bullets for your use and enjoyment. Keep an eye out for new additions to our product line!

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April 26th, 2016

How NOT to Ventilate Your Chronograph — Set-Up Tips

chronograph placement, shooting chrony, chrono, advisory, tech tip

There is nothing more frustrating (or embarassing) than sending a live round into your expensive new chronograph. As the photo below demonstrates, with most types of chronographs (other than the barrel-hung Magnetospeed), you can fatally injure your expensive chrono if it is not positioned precisely.

When setting up a chrono, we always unload the rifle, remove the bolt and bore-sight to ensure that the path of the bullet is not too low. When bore-sighting visually, set up the rifle securely on the sandbags and look through the bore, breech to muzzle, lining up the barrel with your aim point on the target. Then (during an appropriate cease-fire), walk behind the chronograph. Looking straight back through the “V” formed by the sky-screens, you should be able to see light at the end of the barrel if the gun is positioned correctly. You can also use an in-chamber, laser bore-sighter to confirm the visual boresighting (see photo).

Laser boresighter chronograph

Adjust the height, angle and horizontal position of the chronograph so the bullet will pass through the middle of the “V” below the plastic diffusers, no less than 5″ above the light sensors. We put tape on the front sky-screen supports to make it easier to determine the right height over the light sensors.

Use a Test Backer to Confirm Your Bullet Trajectory
You can put tape on the support rods about 6″ up from the unit. This helps you judge the correct vertical height when setting up your rifle on the bags. Another trick is to hang a sheet of paper from the rear skyscreen and then use a laser boresighter to shine a dot on the paper (with the gun planted steady front and rear). This should give you a good idea (within an inch or so) of the bullet’s actual flight path through the “V” over the light sensors. Of course, when using a laser, never look directly at the laser! Instead shine the laser away from you and see where it appears on the paper.

chronograph set-up

Alignment of Chronograph Housing
Make sure the chrono housing is parallel to the path of the bullet. Don’t worry if the unit is not parallel to the ground surface. What you want is the bullet to pass over both front and rear sensors at the same height. Don’t try to set the chrono height in reference to the lens of your scope–as it sits 1″ to 2″ above your bore axis. To avoid muzzle blast interference, set your chronograph at least 10 feet from the end of the muzzle (or the distance recommended by the manufacturer).

chronograph laser sky screens

Rifles with Elevated Iron Sights
All too often rookie AR15 shooters forget that AR sights are positioned roughly 2.4″ above the bore axis (at the top of the front sight blade). If you set your bullet pass-through point using your AR’s front sight, the bullet will actually be traveling 2.4″ lower as it goes through the chrono. That’s why we recommend bore-sighting and setting the bullet travel point about 5-8″ above the base of the sky-screen support shafts. (Or the vertical distance the chronograph maker otherwise recommends). NOTE: You can make the same mistake on a scoped rifle if the scope is set on very tall rings, so the center of the cross-hairs is much higher than the bore axis line.

Laser boresighter chronograph

TARGET AIM POINT: When doing chrono work, we suggest you shoot at a single aiming point no more than 2″ in diameter (on your target paper). Use that aiming point when aligning your chrono with your rifle’s bore. If you use a 2″ bright orange dot, you should be able to see that through the bore at 100 yards. Using a single 2″ target reduces the chance of a screen hit as you shift points of aim. If you shoot at multiple target dots, place them in a vertical line, and bore sight on the lowest dot. Always set your chron height to set safe clearance for the LOWEST target dot, and then work upwards only.

Other Chronograph Tips from Forum Members:

When using a chronograph, I put a strip of masking tape across the far end of the skyscreens about two-thirds of the way up. This gives me a good aiming or bore-sighting reference that’s well away from the pricey bits. I learned that one the hard way. — German Salazar

A very easy and simple tool to help you set up the chronograph is a simple piece of string! Set your gun (unloaded of course) on the rest and sight your target. Tie one end of the string to the rear scope ring or mount, then pull the string along the barrel to simulate the bullet path. With the string showing the bullet’s path, you can then easily set the chronograph’s placement left/right, and up/down. This will also let you set the chrono’s tilt angle and orientation so the sensors are correctly aligned with the bullet path. — Wayne Shaw

If shooting over a chrono from the prone position off a bipod or similar, beware of the muzzle sinking as recoil causes the front of the rifle to drop. I “killed” my first chronograph shooting off a gravel covered firing point where I’d not given enough clearance to start with and an inch or two drop in the muzzle caused a bullet to clip the housing. — Laurie Holland

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December 3rd, 2015

Get Info for 3900 Bullets in FREE Online Database

ShooterForum Bullet Database

Here’s a valuable web resource our readers should bookmark for easy access in the future. ShootForum.com offers a vast Bullet Database, which includes roughly 3900 bullet designs in all. We counted nearly 200 different 6mm bullets! The bullet info comes from the makers of QuickLOAD Software. Access to the online database is FREE. Most database entries include Caliber, Manufacturer, Stated Bullet Weight, True Bullet Weight, Length, Sectional Density (SD), and Ballistic Coefficient.* In many cases multiple BCs are provided for different velocity ranges.

The coverage of the Bullet Database is amazing. Manufacturers in the database include: A-Square, Barnaul, Barnes, Berger, Brenneke, Calhoon, CDP, CheyTac, ColoradoBonded, CT, DAG, David Tubb, Delsing, DEWC, DKT, DTK, DYN, Federal, Fiocchi, FMJ, FN, Fortek, FP, Freedom, Frontier, GECO, Gian-Marchet, GPA, GS-Custom, H&N, Hawk, HeviShot, Hirtenberger, Hornady, HP, Igman, IMI, IMI-Samson, Impala, JDJ, JLK, Klimovsk, Lapua, LEADEx, LEE, Lehigh, LIMA, LostRiver, LYM, MEN, Mil, Norinco, Norma, NorthFork, Nosler, PMC, PMP, Powell, PrviPartizan, Rainier, RCBS, Reichenberg, Remington, RN, RNFP, RUAG, RWS, Sako, Sellier-Bellot, Shilen, Sierra, Sinterfire, Speer, Stoklossa, SWC, Swift, Swiss, The Gun Haus, TMJ, WestCoast, Winchester, WM-Bullets and Woodleigh.

The database is great if you’re looking for an unusual caliber, or you want a non-standard bullet diameter to fit a barrel that is tighter or looser than spec. You’ll find the popular jacketed bullets from major makers, plus solids, plated bullets, and even cast bullets. For those who don’t already own QuickLOAD software, this is a great resource, providing access to a wealth of bullet information.

Values for Changed Bullet Designs
Some of our readers have noted some variances with BCs and OALs with recently changed bullet designs. In general the database is very useful and accurate. However, as with any data resource this extensive, there will be a few items that need to be updated. Manufacturers can and do modify bullet shapes. Kevin Adams, one of the creators of the database, explains: “Thanks for mentioning this database. It took us a long time to collate this information and have agreement to publish it. Please keep in mind that individual batches of bullets will differ from the manufacturers’ stated standards. This is more a reflection on the manufacturers’ tolerances than the database ‘accuracy’. We will continue to add to the database as more manufacturers’ figures come available.”

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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.

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September 23rd, 2015

Pointing Basics — How to Use a Bullet Pointing Die System

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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August 21st, 2015

Awesome Deal on Hornady Bullets — $7.73 Per Hundred (in Bulk)

Midsouth Shooters Supply Free Shipping .223 Rem .224 Bulk Bullets varmint soft point Hornady

Need a boatload of bullets for varmint safaris, or high-volume AR-platform training sessions? Then check out this deal from Midsouth Shooters Supply. Right now you can get six THOUSAND .22-Cal 55gr softpoint bullets for $463.66 delivered. That works out to just $7.73 per 100 bullets. And yes, for a limited time, that price includes FREE Shipping (through August 28, 2015). If you have high-volume applications for .224-diameter projectiles, this deal is hard to beat. You could easily pay two to three tiems as much (per hundred) for similar bullets elsewhere. Buying in bulk saves big bucks.

Midsouth Shooters Supply Free Shipping .223 Rem .224 Bulk Bullets varmint soft point Hornady

These 55g Soft Point bullets are made by Hornady. The G1 Ballistic Coefficient (BC) is 0.243. Hornady says these bullets have a “match-grade jacket design” and offer “explosive expansion, even at low velocities”. NOTE: Midsouth also offers Hornady FMJ 55gr 22-cal bullets at low bulk prices.

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January 11th, 2015

NEW PolyCase Ammunition and Injection-Molded Bullets

Georgia-based PolyCase Ammunition has developed innovative polymer-based composite cartridge cases and injection-molded bullets. With a patent-pending design, the polymer cartridge cases are lighter than brass or steel cases, yet are heat-tolerant, and relatively easy to manufacture. These cases will be initially produced for .223 Remington, plus a variety of pistol cartridge types (.380 ACP, .38 SPL, 9mm Luger). PolyCase cartridge cases blend patented heat-resistent polymers with metal elements in the case base. According to the manufacturer, “the net effects are greatly reduced weight (compared to comparable loaded ammunition), durability… and competitive pricing.” Other companies have experimented with polymer cartridge cases in the past — none have successfully perfected the technology in a commercially successful product. Could PolyCase be the first?

Polymer Polycase Ammunition injection molded bullets Georgia

PolyCase Ammunition — Material Characteristics
– PolyCase Pistol Cartridge Cases are 11.5 to 20% lighter than brass-cased ammunition.
– PolyCase Rifle Cartridge Cases are 23 to 60% lighter than brass-cased ammunition.
– PolyCase Cartridge Cases are self-lubricating — a positive factor compared to brass or steel cases.

Polymer Polycase Ammunition injection molded bullets Georgia

PolyCase Bullets — Injection-Molded Blend of Copper and Plastic
PolyCase has developed its own unique bullets for use in pistol ammunition. PolyCase Cu/P™ bullets are precision injection-molded from a cutting-edge copper-polymer compound. These molded bullets will be offered in both polymer cases and conventional brass cases. (Early in the design process, PolyCase determined that molded bullets work well in both brass and plastic cases). PolyCase co-owner Paul Lemke (Lt. Col. U.S. Army, Ret.) says: “We are able to use essentially the same molds to produce bullets for brass casings and bullets for our polymer casings”.

PolyCase Pioneers Injection-Molded Bullet Technology
Powdered metal has been around for decades, but blending powdered metal with polymers and injection molding precise parts is a fairly modern process. While processes like sintered metal bullets and pressure-formed shotgun pellets have become commonplace, PolyCase is the first American company to produce and sell a completely injection-molded bullet.

Polymer Polycase Ammunition injection molded bullets Georgia

For over a century most bullets have been mass-produced with a process called cold-forming. Lead and copper were shaped with brute force in punches and dies to create projectiles. While this is still a viable and effective way to produce bullets, other manufacturing methods are now available. By applying injection-molding technology, Polycase has developed a new type of bullet that has many advantages, as least for handgun applications. Bullets weigh approximately 70% as much as lead bullets with similar profiles. Lighter weight means higher velocities and less recoil. In addition, PolyCase bullets are lead-free, and low ricochet — two qualities important for indoor and close-range training. The injection-molding process also reduces weight variations (compared to cast lead bullets), and ensures excellent concentricity. Molding also allows unique shapes that are impossible to produce with conventional bullet-making methods (see photo).

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September 19th, 2014

Tech Tip: Try Rotating Cartridge During Bullet Seating Process — This Might Reduce Bullet Run-Out

Redding Competition DieHere is a simple technique that can potentially help you load straighter ammo, with less run-out. It costs nothing and adds only a few seconds to the time needed to load a cartridge. Next time you’re loading ammo with a threaded (screw-in) seating die, try seating the bullet in two stages. Run the cartridge up in the seating die just enough to seat the bullet half way. Then lower the cartridge and rotate it 180° in the shell-holder. Now raise the cartridge up into the die again and finish seating the bullet.

Steve, aka “Short Range”, one of our Forum members, recently inquired about run-out apparently caused by his bullet-seating process. Steve’s 30BR cases were coming out of his neck-sizer with good concentricity, but the run-out nearly doubled after he seated the bullets. At the suggestion of other Forum members, Steve tried the process of rotating his cartridge while seating his bullet. Steve then measured run-out on his loaded rounds. To his surprise there was a noticeable reduction in run-out on the cases which had been rotated during seating. Steve explains: “For the rounds that I loaded yesterday, I seated the bullet half-way, and turned the round 180 degrees, and finished seating the bullet. That reduced the bullet runout by almost half on most rounds compared to the measurements from the first test.”

run-out bullet

run-out bullet

Steve recorded run-out measurements on his 30BR brass using both the conventional (one-pass) seating procedure, as well as the two-stage (with 180° rotation) method. Steve’s measurements are collected in the two charts above. As you can see, the run-out was less for the rounds which were rotated during seating. Note, the change is pretty small (less than .001″ on average), but every little bit helps in the accuracy game. If you use a threaded (screw-in) seating die, you might try this two-stage bullet-seating method. Rotating your case in the middle of the seating process won’t cost you a penny, and it just might produce straighter ammo (nothing is guaranteed). If you do NOT see any improvement on the target, you can always go back to seating your bullets in one pass. READ Forum Thread….

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August 6th, 2014

Berger Updates Free Online Bullet Stability Calculator

Berger Bullets has improved its online stability calculator. Tests have shown that bullets can suffer from reduced BC if the bullet rpm (spin rate) is less than optimal, even if barrel twist rate is otherwise fast enough to stabilize bullets in flight. Now, the improved, free Stability Calculator can determine if you need a faster-twist barrel to enjoy the best BC from your bullets.

CLICK HERE for FREE Berger Twist Rate Stability Calculator

By Bryan Litz, Chief Ballistician for Berger Bullets
We’re happy to announce a major upgrade to our Twist Rate Stability Calculator which is free to use on the Berger Bullets webpage. The old stability calculator was pretty basic, and would simply return a gyroscopic stability number based on your bullet, twist rate, and atmospheric conditions. This was used to determine if your barrels twist rate was fast enough to stabilize a particular bullet or not, based on the Gyroscopic Stability Factor (SG) being greater than 1.4.

Berger Bullet Stability Calculator Twist Rate Bryan Litz

Stability and BC — How Bullet RPM Affects Ballistic Coefficients
The new calculator still calculates SG, but also goes much further. In addition to calculating stability, the upgraded calculator can also tell you if your stability level is harming the effective BC of your bullets or not. Extensive testing has proven that bullets fired with stability levels between 1.2 and 1.5 can fly with excellent precision (good groups), but suffer from a depressed BC, sometimes as much as 10%. Shooting the bullets from faster twist rate barrels allows for the bullets to fly better and realize their full BC potential.

Berger Bullet Stability Calculator Twist Rate Bryan Litz

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