The way you drop powder in the case will affect your max powder volume and the load density. Look at the photo above. These photos show the SAME 30.6 grains of powder using four different fill methods. If you are working with a powder that is below max safe pressure at your current “full case” (with room left for the bullet), and you want to get more velocity with that powder, consider a different case-filling technique.
Most of us assume that if we weigh our powder carefully (down to the tenth of a grain or less) we can achieve a uniform powder fill from case to case in our handloads. Weighing does ensure that the weight of the propellant in each case is the same, but is the column of powder the same by volume each time? “Not necessarily” is the answer. An interesting experiment by our friend Boyd Allen demonstrates that the manner in which you place kernels in the case can make a significant difference in the height of the powder column within the brass case.
Using a Gempro 250 scale, Boyd measured exactly 30.6 grains of Vihtavuori N-133 powder. He then inserted this powder in the same cartridge case multiple times. (The case has a fired primer in place.) But here is the key — Boyd used various filling techniques. He did a slow fill, and a fast fill, and he also experimented with tapping and drop tubes. What Boyd discovered was that you can start with the exact same weight of powder (in fact the very same set of kernels), yet end up with vary different fill heights, depending on how you drop the kernels into the case. Look at the photos. Despite variations in lighting, the photos show the same 30.6 grains of powder, placed in the same cartridge, with four different methods.
Using funnels with long drop tubes packs kernels more tightly, creating a shorter powder column. That allows you to get more propellant (by weight) into the case.
Boyd Explains the Procedure Used for his Experiment.
EDITOR’s NOTE: So there is no misunderstanding, Boyd started with a weighed 30.6 grain charge. This identical charge was used for ALL four fills. After a fill the powder was dumped from the case into a pan which was then used for the next fill technique to be tried. So, the powder weight was constant. Indeed the exact same kernels (of constant weight and number) were used for each fill.
Boyd writes: “I used the same powder for all fills, 30.6 gr. on a GemPro 250 checked more than once. All fills employed the same RCBS green transparent plastic funnel. The fast drop with the funnel only overflowed when it was removed from the case neck, and 15 granules of powder fell on the white paper that the case was sitting on. The fast-funnel-only drop with tapping, was done with the funnel in place and the case and funnel in one hand, while tapping the case body with the index finger hard, many times (about 20 fast double taps). My idea here was to “max out” the potential of this tapping technique.
The slow drop with the funnel and 10″-long .22 cal. Harrell’s Precision drop tube, was done by holding the scale pan over the funnel and tapping the spout of the pan repeatedly on the inside of the funnel about 1/3 down from the top, with the scale pan tilted just enough so that the powder will just flow. Many taps were involved, again, to max out the technique.
Again, to be clear, after each case filling, the powder was poured from the case back into the scale pan carefully. You may notice the similarity between the fast drop with the drop tube, and the funnel only with tapping. Although I did not photograph it, fast tube drop and tapping (combined) improved on tapping alone, but only to about half as far down the neck as the slow with drop tube. Due to the endless possible permutations, I picked four and left it at that.
I believe that I can make the rough judgment that the scale pan funnel and drop tube technique, which involved a longer drop period, and probably less velocity at the top of the tube, left more room in the top of the case neck than the slow drop from the measure with the same drop tube. You have both pictures, so you can make the comparison.” — Boyd
Does Powder Column Height Variance Make a Difference?
Boyd’s experiment proves pretty conclusively that the method of dropping a given weight of powder can affect the height of the powder column in the case and the degree of powder compression (when a bullet is seated). He showed this to be true even when the exact same set of kernels (of constant weight) was used in repetitive loadings. This raises some interesting questions:
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.
Sinclair Internationalhas 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 Accuracyby 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.
Figure 1: The cartridge.
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).
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.
Figure 4: Neck in alignment with center of the case axis.
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″.
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”.
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.
Figure 8: Proper alignment from the center of the case head to the tip of the bullet.
(NOTE: This links to a Web Archive version of older Sinclair Int’l article.)
*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.
The U.S. Army Marksmanship Unit publishes reloading “how-to” articles on the USAMU Facebook page. One Wednesday “Handloading Hump Day” post covered preparation of once-fired 5.56x45mm brass. This article, the first in a 3-part series, has many useful tips. If you shoot a rifle chambered in .223 Rem or 5.56x45mm, this article is worth reading. And visit the USAMU Facebook page for other hand-loading tips.
This week, Handloading Hump-Day will answer a special request from several competitive shooters in Alaska. They asked about procedures for morphing once-fired GI 5.56mm brass into accurate match brass for NRA High Power Rifle use. The USAMU has used virgin Lake City (LC) 5.56 brass to win National Championships and set National Records for many years. In this 3-part series, we’ll share techniques proven to wring match-winning accuracy from combat-grade brass.
Preparing Once-Fired GI 5.56 Brass for Reloading (Part 1 of 3)
Assuming our readers will be getting brass once-fired as received from surplus dealers, the following steps can help process the low-cost raw material into reliably accurate components.
1. Clean the Brass
First, clean the brass of any dirt/mud/debris, if applicable. Depending on the brass’s condition, washing it in a soap solution followed by a thorough rinsing may help. [This step also extends the life of the tumbling media.] Approaches range from low-tech, using gallon jugs 1/2 full of water/dish soap plus brass and shaking vigorously, to more high-tech, expensive and time-consuming methods.
2. Wet-Tumbling Options (Be Sure to Dry the Brass)
When applying the final cleaning/polish, some use tumblers with liquid cleaning media and stainless steel pins for a brilliant shine inside and out, while others take the traditional vibratory tumbler/ground media approach. Degree of case shine is purely personal preference, but the key issue is simple cleanliness to avoid scratching ones’ dies.
Shown below are Lake City cases after cleaning with Stainless Media (STM). Note: STM Case cleaning was done by a third party, not the USAMU, which does not endorse any particular cleaning method.
If a liquid cleaner is used, be SURE to dry the cases thoroughly to preclude corrosion inside. One method is to dump the wet brass into an old pillow case, then tilt it left/right so the cases re-orient themselves while shifting from corner to corner. Several repetitions, pausing at each corner until water stops draining, will remove most water. They can then be left to air-dry on a towel, or can be dried in a warm (150° F-200° F max) oven for a few minutes to speed evaporation.
3. Inspect Every Case
Once dry, inspect each case for significant deformation (i.e., someone stepped on it), damaged mouths/necks and case head/rim damage. Some rifles’ ejectors actually dig small chunks of brass out of the case head — obviously, not ideal for precision shooting. Similarly, some extractors can bend the case rims so badly that distortion is visible when spinning them in one’s fingers. These can be used for plinking, but our match brass should have straight, undamaged rims.
Dented case mouths are common, and these can easily be rounded using a conical, tapered tool, [such as a .223 expander mandrel. A dummy 7.62 or .30-06 cartridge with a FMJ spitzer can also work.] If most of your brass is of one headstamp, this is a good time to cull out any odd cases.
4. Check the Primers Before Decapping
Your clean, dry and inspected brass is now ready for full-length sizing, decapping and re-priming. Historically, primer crimps on GI brass have caused some head-scratching (and vile language) among handloaders. Our next installment will detail efficient, easy and practical methods to remove primer crimp, plus other useful handloading tips. Until next week, Good Shooting!
NOTE: The USAMU Handloading (HL) Shop does not RE-load fired 5.56 brass. We use virgin LC brass with our chosen primer already staked in place. However, our staff has extensive personal experience reloading GI brass for competition, which will supplement the Shop’s customary steps. In handloading, as in life, there are many ways to accomplish any given task. Our suggestions are note presented as the “only way,” by any means. Time for loading/practicing is always at a premium. Readers who have more efficient, alternative methods that maintain top accuracy are invited to share them here.
Hodgdon and IMR powders, including H4198, Varget, H4350, and IMR 4451, are some of the most successful propellants used by competitive shooters. If you want to find solid, reliable load data for these and other Hodgdon and IMR powders, we recommend you go right to the source — visit the Hodgdon/IMR Reloading Data Center, at www.HodgdonReloading.com. There you’ll find the latest, updated load recipes for pistol, rifle, and shotgun reloaders.
In the Data Center, you’ll find thousands of load recipes for pistol, rifle, and shotgun. Rifle shooters will find dozens of loads for their favorite Hodgdon, IMR, and Winchester powders such as H4198, Varget, H4350, and IMR 8208 XBR. And Hodgdon’s Reloading Center is now faster and easier to use. Navigation is simplified and the whole interface is more user-friendly.
Precise Search Results for your Cartridge and Favorite Powders
The online Reloading Data Center allows you to get precise search results for any listed cartridge. You can select your preferred powders and bullets. After choosing a cartridge, you can pre-select specific bullet weights and powder types. That quickly delivers just the information you want and need. You won’t have to scroll through scores of entries for bullets or powders you don’t use.
Data Center Works Well with Mobile Devices
Mobile users will notice Reloading Center is very “user-friendly” for smart-phone and tablet users. Controls have been optimized for touch-screens, and buttons are large and easy to use. Likewise the results are displayed in a large, easy-to read format.
Hodgdon tip from EdLongrange. We welcome reader submissions.
Our friend Erik Cortina is at Raton, NM this week at the F-Class Nationals. When he’s not shooting (or working) Erik produces YouTube videos. One of his most popular videos explained why you should full-length size cartridge brass. In no uncertain terms Erik says: “Quit Neck Sizing!!!” Watch the Video:
Why It’s Smart to Full-Length Size Your Brass
Commentary by Erik Cortina
Should You Full-Length Size Your Cartridge Brass?
Absolutely. Let Me Explain Why…
I have seen it time and time again, shooters on the line wrestling with their rifle trying to get the bolt closed while the wind is switching. They were too focused trying to get their bolt to close and getting their rifle settled back on the bags that they missed the wind switch. Bang… Eight! The straw that broke the camel’s back for me was at the 2017 Canadian Nationals. I was paired up with a young girl and she would try really hard to close the bolt on her rifle. The majority of the time she would get it to close, but often times she could not even get the round to chamber. She was focused on her rifle the entire time rather than on the conditions. When we completed our strings, she had five rounds that did not chamber our of 15! That is way too many!. I told her she needed to think about Full-length sizing with 0.002″ shoulder bump, or Controlled Full-length Sizing like I call it. I told her not to worry about losing accuracy. I told her that I full-length size all my rounds and asked if she noticed how smooth my bolt was and noticed my score. She said yes, they were both great!
Controlled Full-length Sizing Does NOT Harm Accuracy
I have found that Controlled Full-length Sizing does NOT hurt accuracy or shorten brass life. I find that I can focus much more on the conditions when I don’t have to think about chambering a round nor extracting it. It has become second nature. After firing, I keep my head welded to the stock, I open the bolt by placing my thumb on top of stock and rotating hand upwards. I reach in and retrieve spent case, place it back in ammo box, and pick up another loaded round and put in chamber. I verify conditions and when ready, I push the bolt in and close it with my index and middle finger.
With Controlled Full-length Sizing you “bump” the shoulder around .002″ for bolt guns.* Image courtesy Sinclair International which carries a variety of Full-length dies.
Whidden Full-Length Sizing Dies by AccurateShooter.com Editor
For proper Full-length sizing, you want a quality die that’s a very good match to your chamber. For our project rifles we usually turn to Whidden Gunworks which offers both bushing and non-bushing FL dies. And if you want the hot new option, check out Whidden’s patent-pending, click-adjustable FL-sizing die. This gives instant, precise control over shoulder bump. It works great.
*With gas guns, such as the AR10, you may want to increase shoulder bump to .003″ or more. With some benchrest cartridges, .0015″ bump may prove optimal. But .002″ is a good starting point.
Who doesn’t want to save money? If you can get a significant discount, you should really take advantage of that opportunity. Guys, we’ve been tracking prices on shooting sports products at vendors around the country. Sad to say, we’ve seen price increases across the board in 2019. Reloading components, loading tools, stocks, targets, electronic gadgets — you name it, the price trend is moving upwards. Thankfully our friends at Precision Reloading are holding the line. Even better, Precision Reloading is running a really significant promotion right now.
Take Note! For today and tomorrow, January 16 and January 17, you can get 15% OFF All ORDERS over $100.00. That’s right, save 15% on your purchases at Precision Reloading with Code 15OFF. If you buy a $400.00 item that could save you $60.00. Yes, this applies to pretty much everything in stock at Precision Reloading, including all major brands below (and dozens more including Lapua, Berger, Forster, Hodgdon, Nosler, RCBS, Redding, Sierra etc.).
If you need bullets, brass, powder, dies, presses, powder dispensers, check out this sale. It’s a very good deal. Use Code 15OFF at check-out to save 15% on your orders over $100.00.
You’ll find lots of notable new products in Shooting Industry’s January 2019 issue. This 108-page issue is filled with timely articles ranging from marketing insights and SHOT Show 2019 coverage to tips for success in the new year. The January issue also includes Part II of the 2019 New Product Showcase. January’s 30-page New Product Showcase features over 150 products from 115 brands. Here are some highlights from the Product Showcase:
Steyr’s Monobloc — Barrel and Action are one piece of steel. Impressive engineering, but what happens when your barrel wears out?
Berger has new 6mm Creedmoor Ammo plus new .375-Caliber bullets for ELR shooters:
Lyman has a great new Case Trimmer with speed control and carbide cutter:
New Brass from Jagemann and BOG “DeathGrip” Clamping Tactical Tripod:
New Generation Mantis — Accelerometer and software tracks your muzzle movement:
Have a LONG F-Class Rifle or a PRS rig with suppressor? This nice case will hold your rig:
MORE SHOT Show Coverage
Shooting Industry’s January Issue has extensive SHOT Show coverage, including the comprehensive Exhibitors Guide, SHOT Show Auction info, plus a sizable pullout map in the printed editions.
Harrell’s Precision sells “semi-custom” full-length bushing dies for the PPC and 6BR chamberings. While the Harrell brothers do not cut the die to spec, they carry a large selection of dies made with slightly different internal dimensions. When you send in your fired brass, the Harrells choose a die from inventory with just the right amount of sizing (diameter reduction) at the top and bottom of the case. Given the quality, and precise fit, Harrell’s full-length dies are a good value at $75.00 plus shipping.
Bump Measuring Collar
The Harrell brothers provide a nice bonus item with each full-length die — a neat, little shoulder bump measuring device as shown in the photo at right. Hornady/Stoney Point sells a stand-alone tool that does the same job, but the Harrell’s bump collar is simpler and faster. To measure your shoulder bump, simply place the Harrell’s bump collar over the front of your deprimed case (before sizing) and measure the OAL with your calipers. Then size the case in your full-length die, replace the collar and repeat the measurement. You want to set your die so the shoulder moves back about .001″ to .0015″ for most applications. (With semi-auto guns you may want more bump.)
Clearance Check — Remove the seating stem and drop a bullet into it. The farther down the ogive or nose-cone the step recess grips the bullet, the better. If it’s only pressing down against the bullet tip, a crooked seat is assured, along with inconsistent seating depth. — Glen Zediker
Some folks acquire a new seating die and then are surprised to find their hand-loads show crooked bullets and/or inconsistent seating depth. The problem could be a mis-match between the bullet and the die’s seating stem. In some case, particularly with long, streamlined bullets, the bullet tip can actually touch the bottom inside of the stem. This can cause a variety of problems, as Glen Zediker explains…
Invest in a Good Seating Die Reloading Tip by Glen Zediker
The bullet seating operation is the “last thing” that happens and it’s also the one thing that can corrupt the care and treatment given to the quality of the loaded round prior. A sleeve-style seater, well-machined, goes a whopping long ways toward preserving alignment, and, therefore, concentricity. Also make sure that the stem in yours comes to rest well down onto the bullet ogive, and, above all else, is not contacting the bullet tip! That will wreck a round.
If you have this problem, you should contact the die maker — some will offer a different seating stem expressly designed for longer, pointier bullets. This “long bullet stem” will normally drop right into your existing die. If you plan to run long, VLD-style bullets you should request the special seating stem right from the get-go.
Bump Measuring Collar
