German Salazar, a top small-bore and centerfire shooter, uses the 6XC cartridge in some long-range matches. German has tried a variety of different types of brass for this cartridge, including necked-up 22-250 brass and Norma 6XC brass from David Tubb’s (Superior Shooting Systems). German’s measurements reveal significant differences in water capacity, as well as neck-wall thickness.
6XC Source Brass Dimensions
Case Capacity and Pressure Issues
German has noted significant variances in capacity among the different “flavors” of brass. Norma-headstamp 6XC brass has 49.3 grains of H20 capacity, while Norma 22-250 brass holds only 47.8 grains of H20. Third-generation Tubb-brand 6XC brass is somewhere in the middle, with 48.6 grains of capacity. German did not have a chance to measure the high-quality Lapua 22-250 brass introduced in 2010. NOTE: These differences in case capacity are large enough that you MUST adjust your load to the brass type.
We ran a 6XC QuickLOAD simulation with 115gr bullets and H4350 powder. QuickLOAD predicted that the observed difference in case capacity can result in pressure differentials as much as 4,500 psi! In other words, if you switch from Norma 6XC brass to a lesser-capacity brass type, your pressures could rise 4,500 psi (using H4350 and 115gr bullets).
We recommend sticking with the Norma 6XC brass. It is available from DavidTubb.com for a reasonable $69.00 per 100 cases. These days, that’s cheaper than many other types of premium imported cartridge brass.
Neck Thickness and Chambering Issues
German noted that the different types of available brass varied quite a bit in neck-wall thickness — from 0.0121″ (Norma 22-250) to 0.0140″ (Tubb 3rd Gen). Consequently the diameter of loaded rounds also varied. Depending on the brass you chose, your loaded rounds could be 0.267″ at the neck or 0.271″ (with no-turn brass). That’s a huge difference and it’s something you need to take into account when you have your chamber cut for a barrel. For a cross-the-course rifle, you might want a chamber with at least .003″ total clearance over a loaded round. Obviously, to achieve that clearance, you’ll need to set chamber dimensions base on your preferred type of brass.
NOTE: The research for this story was conducted in 2010. Dimensions may have changed with more recent production, so you should double-check the case capacity of your own 22-250 or 6XC brass.
Successful long-range shooters know that careful weighing of powder charges helps them achieve superior long-range accuracy. By maintaining powder charges within very narrow weight tolerances, hand-loaders can produce ammo with more consistent muzzle velocities from shot to shot. Low Extreme Spread (ES) and Standard Deviation (SD) numbers translate directly to reduced vertical dispersion at very long ranges (although velocity is not the only contributing factor to vertical spread). In pursuit of load weight uniformity, many of our top long-range aces have invested in the latest, high-tech magnetic force restoration (MFR) digital scales (such as the Sartorius GD503). These laboratory-grade MFR scales are extremely stable (with minimal drift) and they can reliably measure to .005 grain, that is five thousandths of a grain. That is less than the weight of one kernel of typical extruded powder. For example, with Varget, there are three to four kernels in one-tenth of one grain of Varget. That means each kernel weighs .025 to .035 grains.
With the capability of modern modern MFR scales to measure less than one-hundreth of a grain, we have a new frontier in precision reloading. You’ll note, in the preceding paragraph, we said that one-tenth of one grain of Varget is three or four kernels. Well, “which is it?” you might ask. The answer is that it might be three, or it might be four, depending on the size of the individual kernels. That’s a disturbing uncertainty that we simply had to accept… until now.
Powder Kernel Uniforming — A Breakthrough
We now have the tools and the methodology to resolve the inherent uncertainty in individual kernel weight. Using the new technique of powder kernel uniforming, first pioneered by German Salazar, we can now, for the first time, ensure that every kernel of powder that goes into a cartridge is virtually the same weight — the same, in fact, within 0.01 grain (one-hundredth of a grain) TOTAL spread.
For a reloader looking to achieve “perfect” load weight uniformity, powder kernel uniforming offers the ultimate control over powder weight. The method we devised to uniform individual kernels consists of kernel core-drilling. The propellant we chose for this kernel-uniforming test was a new prototype (not yet commercially available) EuroChemie RL “X” propellant. This was chosen because it offered relatively large, can-shaped kernels that could be drilled relatively easily.
Core-Drilling Kernels with Micro Drill-Bits
The center of each kernel was bored out with a micro-drill. But here’s the key. Before drilling, we first weighed each kernel. Then we selected a micro drill bit of appropriate diameter to achieve uniform weights. With the heavier kernels (in the 0.04 gr range) we used a larger micro-bit. With the lighter kernels (in the 0.02 range), we selected a smaller diameter micro-bit that removed less material from the center of the kernel. Obviously, many kernels were ruined while we perfected the drilling process. It required great patience and a very steady hand. But after a few dozen hours of drilling, we had a batch of uniformed kernels that were all within plus or minus .005 grains (.01 grain ES). Now we were ready to do some testing.
Proof That It Works
All this time-consuming work to drill holes in individual kernels would be pointless, of course, if it did not produce meaningful accuracy gains. The proof, as they say, is “on the target”. We were curious to see if our uniformed powder kernels would out-perform unmodified kernels, so we did some field testing. We prepared two batches of 6mmBR ammo in Lapua brass, with full case prep, and bullet base to ogive sorting (we wanted to eliminate as many variables as possible). Bullets were Lapua 105gr Scenar Ls, which proved to be some of the most consistent projectiles we’ve ever measured.
One set of rounds was loaded with a carefully-weighed charge of unmodified kernels. Case to case charge weight was held to .05 grain (half a tenth uniformity). Then we prepared a second batch of cartridges with uniformed kernels, using the exact same charge weight, also held to .05 grain (half a tenth) tolerances. We took these rounds to the range, and did a “round-robin” test at 800 yards, shooting one of each type in sequence (i.e. one uniformed on right, then one non-uniformed on left) until we had two 10-round groups. The test was done with a rail gun fitted with a 1:8″ twist, 28″ Krieger 0.236″ land barrel. The uniformed-kernel ammo was shot at the right diamond, while the non-uniformed rounds were shot at the left diamond. Conditions were good, so we simply “held center” on every shot. No attempt was made to correct for wind as our primary concern was vertical dispersion.
Ammo with Uniformed Kernels Shows Significantly Less Vertical Dispersion at Long Range
As you can see, the uniformed-kernel ammo out-performed the non-uniformed ammo. The difference is quite clear. The rounds with non-uniformed kernels (on the left) produced a 10-shot group with roughly 3.0 inches of vertical dispersion. On the right, our ammo with uniformed kernels produced a group with 9 of 10 shots showing roughly 1.75 inches of vertical dispersion (we did have one high flier among the uniformed-kernel rounds). Additionally, we had a lower 10-shot ES and SD with the uniformed-kernel ammo. We repeated this test two more times and the results were similar. The targets speak for themselves. If you are looking for ultimate long-range accuracy, powder kernel uniforming is a “new frontier” you may wish to explore. With all other factors held constant, we were able to reduce vertical dispersion by more than an inch at 800 yards by drill-uniforming our NitroChemie powder. That’s huge in the long-range game.
Yes, the kernel-uniforming process is incredibly time-consuming and tedious, and a set of micro-drills is not cheap. We also freely acknowledge that the process may be much less productive with narrow-kernel propellants that are hard to drill. (Also EuroChemie powders are preferred because the burn rate controlling compounds are impregnated throughout the entire kernel — not just the outside.) But the potential for significant accuracy gains is there. We proved that.
Is it worth the huge investment of time to drill your powder kernels? That’s a question each reader must ask himself. But if you know the competitor on the next bench over has uniformed his kernels, can you afford not to do the same? Sometimes the extra effort is worth it, just for the peace of mind you get knowing you’ve done everything possible to achieve “ultimate accuracy”.
Next time you have a barrel fitted, consider having your gunsmith create a “stub gauge” from a left-over piece of barrel steel (ideally taken from your new barrel blank). The outside diameter isn’t important — the key thing is that the stub gauge is created with the same reamer used to chamber your current barrel, and the stub must have the same bore diameter, with the same land/groove configuration, as the barrel on your rifle. When properly made, a stub gauge gives you an accurate three-dimensional model of the upper section of your chamber and throat. This comes in handy when you need to bump your case shoulders. Just slide a fired case (with spent primer removed) in the stub gauge and measure from base of case to the end of the gauge. Then, after bumping, re-measure to confirm how much you’ve moved the shoulder.
In addition, the stub gauge lets you measure the original length to lands and freebore when your barrel was new. This gives you a baseline to accurately assess how far your throat erodes with use. Of course, as the throat wears, to get true length-to-lands dimension, you need take your measurement using your actual barrel. The barrel stub gauge helps you set the initial bullet seating depth. Seating depth is then adjusted accordingly, based on observed throat erosion, or your preferred seating depth.
Forum member RussT explains: “My gunsmith [makes a stub gauge] for me on every barrel now. I order a barrel an inch longer and that gives him enough material when he cuts off the end to give me a nice case gauge. Though I don’t have him cut that nice-looking window in the side (as shown in photos). That’s a neat option. You can tell how much throat erosion you are getting from when it was new as well. For measuring initial seating depths, this is the most useful item on my loading bench next to calipers. Everyone should have a case gauge made by there smith if you have a new barrel put on.”
Forum member Lawrence H. has stub gauges made with his chamber reamers for each new barrel. He has his smith cut a port in the stub steel so Lawrence can actually see how the bullet engages the rifling in a newly-cut chamber. With this “view port”, one can also see how the case-neck fits in the chamber. Lawrence tells us: “My stub gauges are made from my barrels and cut with my chamber reamers. With them I can measure where my bullets are ‘touching the lands’ and shoulder bump dimensions. This is a very simple tool that provides accurate information.” To learn more about stub gauges, read this Forum Thread. The photos above and below show Lawrence’s stub gauges:
For years, many shooters have coated bullets with Moly (molybdenum disulfide) or Danzac (tungsten disulfide or “WS2″). The idea was to reduce friction between bullets and barrel. In theory, this could lengthen barrel life and extend the number of rounds a shooter can fire between cleanings.
Moly and WS2 both have their fans, but in the last couple of years, some guys have switched to Hexagonal Boron Nitride (HBN), another dry lubricant. The advantage of HBN is that it won’t combine with moisture to create harmful acids. HBN is very slippery and it goes on clear, so it doesn’t leave a dirty mess on your hands or loading bench. Typically, HBN is applied via impact plating (tumbling), just as with Moly.
HBN Results — Both on Bullets and Barrel Bores
Many folks have asked, “Does Hexagonal Boron Nitride really work?” You’ll find answers to that and many other questions on gunsmith Stan Ware’s popular Bench-Talk.com Blog. There Paul Becigneul (aka Pbike) gives a detailed run-down on HBN use, comparing it to other friction-reducers. Paul also discusses the use of HBN in suspension to pre-coat the inside of barrels. Paul observes:
We coated our bullets … how we had been coating with WS2. Now our bullets have a slightly white sheen to them with kind of like a pearl coat. They are so slippery it takes a little practice to pick them up and not drop them on the trailer floor. What have we noticed down range? Nothing different from WS2 other than the black ring on your target around the bullet hole is now white or nonexistent. Our barrels clean just as clean as with WS2. Your hands aren’t black at the end of the day of shooting and that might be the most important part.
Interestingly, Becigneul decided to try a solution of HBN in alcohol, to pre-coat the inside of barrels. Paul had previously used a compound called Penephite to coat the inside of his barrels after cleaning. Paul explains:
If Penephite was used because it was slippery wouldn’t HBN be better? … We called Jon Leist again, and talked to him about mixing HBN and 90% alcohol for a suspension agent to pre-lube our barrels. He though it sounded great but that the AC6111 Grade HBN would be better for this use. It would stand up in the alcohol suspension and cling to the barrel when passed through on a patch. We got some from Jonn and mixed it in alcohol 90%. We use about one teaspoon in 16 ounces of alcohol.
We started using it this fall and what we have noticed is that now that first shot fired out of a clean and pre-lubed barrel can be trusted as the true impact point. We use tuners so now I got to the line, fire two shots judge my group for vertical, adjust the tuner as needed or not, and after tune has been achieved go to my record targets. This use has saved us in time at the bench and bullets in the backstop.
You really should read the whole article by Becigneul. He discusses the use of barrel lubes such as Penephite and “Lock-Ease” in some detail. Paul also provides links to HBN vendors and to the Material Safety Data Sheets (MSDS) for the various compounds he tested.
Now through April 6, 2012, Sinclair’s Stainless Micrometer “Ultimate Trimmer” system is on sale for $159.99. That’s a $20.00 savings off the normal $179.00 price. This unit comes complete with micrometer cut-length control, stand, Shark Fin clamp for the case-holder, and a stainless Wilson cutter housing. NOTE: Caliber-specific case-holders are sold separately.
The Sinclair Micrometer head allows reloaders to easily adjust trim length in .001″ increments with an adjustment length of over 2″. The micrometer features easy-to-read, engraved unit markings and may be locked in place. The Ultimate Trimmer can trim cases from 22 Hornet up to 416 Rigby.
The Sinclair Stainless Ultimate Trimmer comes with Sinclair Mounting Stand and handy Shark Fin Clamp. This system makes easy work of installing and removing your trimmer case holder in a smooth “swing-arm” motion. The Shark Fin trimmer clamp secures the case head firmly against the micrometer adjustment head for a quick and accurate, chatter-free trim. NOTE: We have found that you will get the most accurate, repeatable trim lengths if you set the shark fin to a firm tension and do NOT hold the case-holder with your hand — let the Shark Fin clamp do the job. The video below shows how to use a Wilson case trimmer (with micrometer, stand and Shark Fin).
Jeffrey Block has created a great new FREE software program, OnTarget, that measures shot groups quickly and precisely. All you need is a photo or scan of your target. The program allows you to set your target distance, and provides caliber-specific tools to precisely mark the center of each shot. Once you’ve marked each bullet hole, Jeff’s OnTarget program automatically calculates group center, maximum group spread (CTC), average distance to center, group width and height, and group offset from point of aim. The program will even measure multiple groups on the same target.
After just a few minutes spent learning the program’s tool buttons, we were able to plot shot groups on a variety of targets with ease. Once you select the target distance and bullet diameter, figuring group size is a simple matter of centering a circle tool over each bullet hole. Then the program “connects the dots” and provides all the info you could want automatically.
The program worked with bullet holes as small as 17 caliber and as large as 50 caliber. It is very precise, but remember that if your target photo was taken at an angle, distorted perspective can cause slight errors in measurement. Therefore, for the ultimate precision, you want to start with a flat scan of the target.
OnTarget Compared to Measuring Manually
We found OnTarget to be especially useful for groups with widely dispersed bullet holes, or very small bullet holes, such as 17 caliber holes. We’ve found that it’s difficult to measure 17-cal group sizes with a standard caliper, because the tool itself obscures the tiny holes. With OnTarget, the program can zoom up your target view, making it much easier to plot the center of each shot. And with a widely dispersed group of shots, the program automatically finds the two most distant shots. You can’t mistakenly pick the wrong pair of shots to measure.
Flash Tutorial Shows How It Works
Jeff created an excellent animated Animated Tutorial demonstrating OnTarget’s functions. It shows how to import a target image or scan, how to set target distance and scale, how to set bullet size and circle each bullet hole, and how to save the marked and measured target. VIEW OnTarget TUTORIAL
MEASURING REAL TARGETS — Actual Examples
Here are examples we created with OnTarget. The first photo shows a 17 Mach 2 target. These tiny 17-cal holes are notoriously hard to measure. With OnTarget, it’s a snap. You just load the target image into the program, zoom in with the controls, and then click on the center of the holes. The program automatically calculates group size, displaying measurements in both inches and minutes of angle (MOA)
Original Target (with ruler for scale)
Target Captured and Displayed in Program
Detail of Group, Enlarged by Program
10-shot Groups? — No Problem
Here’s another target, showing 6mm bullet holes at 600 yards. The first image shows the target image loaded into the program with the ten holes circled in red.
Target Displayed in Program
For this target we have used the Aiming Point option. The Aim Point was set at the center of the “X” and the program calculates average distance from the Aim Point. Very cool.
Detail of 10-Shot Group, Enlarged by Program
No Scanner Needed
The OnTarget program grabs target scans directly from a flatbed scanner using Microsoft’s Windows Image Acquisition system. But don’t worry if you don’t have a scanner. You can just take a digital photo of your target and OnTarget will import it quickly and easily. To set target scale, a simple tool allows you to mark a known length on the target (such as the diameter of the “X” Ring), and the program will then size the target accordingly. Is OnTarget precise and accurate? Here’s what Forum Member Steve W. says: “I used the extreme spread measurement of a group on one of my 600-yard match targets… as it was officially scored at the match. By clicking the +—+ icon, then clicked the cursor in the centers of the two extreme spread holes, I then entered that value in the reference window. After that it was simple because the bullet placement cursor’s circle was the same size as the black outline of the actual bullet holes on the picture of the target. OnTarget’s measurement came up within .006 of the official 2.772 inch measurement of the group. That’s pretty darned close; well inside the human judgement of aligning the tips of a micrometer on the bullet holes.”
Bottom Line — Great Program — Download It Today
Jeffrey Block has done a great service for shooters by creating the FREE OnTarget program. It is easy to learn, it functions great, and it can save you time and effort measuring targets. It also lets you easily archive and compare multiple targets produced during load development or rifle testing. You can record ammo type, date, location, weather etc. in note fields accessed by “Group Info” and “Target Info” tabs.
Keep in mind that OnTarget was NOT created to replace existing methods for scoring competition targets. But for all other target measuring purposes it does a great job. Visit Jeff’s website, OnTargetShooting.com, view the tutorial, and check out OnTarget for yourselves.
To learn more about OnTarget, see more measuring samples, and read advanced Power-User Tips, visit our full OnTarget Product Review.
Here’s a tip that can help you score higher at matches and get more predictable results when weighing loads with an electronic scale. Kelly Bachand, a top prone shooter and electrical engineering major at the Univ. of Washington, tells us that all digital scales can drift. Therefore Kelly recommends re-calibrating electronic scales often. In addition — and this is key — Kelly recommends that you shoot the ammo in the exact order in which it was loaded. Arrange your loaded ammo in a box in the order of loading and shoot it first-loaded to last-loaded. (Or, if you prefer, shoot it last-loaded to first-loaded.) The important thing is to maintain the order and not mix everything up. That way, if your scale drifts, the effect of drift on charge weight will be incremental from one loaded round to the next, so point of impact change should be negligible. Conversely, if you shoot your last-loaded round right after your first-loaded round, the effect of scale drift is at its maximum, so powder charge varience is maximized. And that can produce a different point of impact (POI) on the target.
Tips on Loading with Electronic Scales by Kelly Bachand
If you use a digital scale to measure powder charges, recalibrate the scale often. I like to do this about every 25 rounds or so. Additionally, most electronic scales rely on eddy currents for their precision. Eddy currents are easily disrupted by static electricity so keep a cloth or ground strap nearby to remove any static currents should the scale start acting up; I usually just use a fabric softener sheet that has gone through the dryer once.
Shoot Ammo in Order of Loading
I shoot my rounds in the same order or reverse order as I load them. If the charge weight varies due to scale drift during use, the difference will be gradual if I shoot in the same order as production (or reverse order). I should be able to adjust for the slight varience in charge weight without having any wildly high or low shots (see the charts below for a graphical demonstration). I usually load my ammunition just 100 rounds at a time. Give yourself plenty of time and remember that you will make your best ammunition when you are fully awake and alert.
This graph demonstrates the effect a .01% (that’s 1/100th of 1 percent) difference in scale measurement would have over the course of 100 rounds assuming the desired load is somewhere between 46 and 47 grains. The final round made would have almost 1% less (or more) powder than the first, that’s almost an 0.5 grain difference from the first. If shot back to back, these rounds will invariably have different points of impact on the target.
This graph demonstrates the same .01% difference in scale measurement but this time with a recalibration every 25 rounds. By recalibrating the scale every 25 rounds the furthest a weighed charge ever gets from the original is less than 0.25%. Again if the charge being weighed is between 46 and 47 grains then the 26th round made would vary from the 1st by .12 grains. Even that small difference would likely show on target.
Either way it is important to note that if the bullets are shot in the same (or reverse) order as they are made, the biggest difference from bullet to bullet in this example is less than .01 grains.
With the price of premium brass topping $90/100 for many popular cartridges, it makes sense to consider annealing your brass to extend its useful life. Forum member Darrell Jones offers a full range of brass prep, brass forming, and brass restoration (annealing, ultra-sonic cleaning) at very affordable prices. Starting at just $15 per 100 cases, Darrell’s company, DJ’s Brass, will anneal your used brass using state-of-the-art Bench-Source annealing machines. He can also ultrasonically clean cases for $15 per 100 ($20 per 100 for magnum cases larger than 0.473″ rim).
Custom Neck-Turning Services
Another great service DJ’s Brass provides is precision neck-turning. He can neck-turn any size case to your specified neck-wall thickness. The price is $0.30 per case (normal size) or $0.40 (magnum size) with a $20.00 minimum order. And if you’ve got a bucket of brass to neck-turn, that’s fine with Darrell — he recently neck-turned 1500 pieces of brass for one customer!
DJ’s Brass can process everything from .17 Fireball all the way up to the big magnum cases. And the job gets done quickly. Darrell has a 10-day turn-around guarantee. For most jobs, Darrell tells us, he gets the processed brass to the Post Office within three business days. DJ’s Brass charges only actual shipping fees, using USPS flat-rate boxes.
• Ultrasonic Cleaning + Annealing ($25.00/100 normal or $30/100 magnum)
• Ultrasonic Cleaning and Polishing ($15.00/100 normal or $20/100 magnum)
• Anneal Case Necks (after checking for splits) ($15.00/100 normal or $20/100 magnum)
• COAL Trim and Chamfer Case Mouths ($0.20 per case, $20.00 minimum order)
• Uniform and Square Primer Pockets ($0.15 per case, $20.00 minimum order)
• Expand Case Necks and Anneal brass (Call for Price)
• Create False Shoulder for Fire-Forming (Call for Price)
Muzzle Brake Tax Break Special: FREE cleaning of up to two (2) Stainless Muzzle Brakes with a minimum $50.00 order. Special good through April 17, 2012 (Tax Return Deadline for 2012).
DJ’s Brass Offers Specialized Custom Services
Darrell tells us: “At DJ’s Brass, we can handle all your brass refurbishing needs. From ultrasonic cleaning to custom annealing for specific wildcat cartridges. We can expand your necks from .22 caliber to .30 caliber and anneal shoulders for consistent bump-back. We can turn your case-necks and trim the brass to your specs. For some cartridge types, I can pre-form cases to assist in fire-forming a wildcat cartridge. We also remove the carbon build-up in muzzle brakes. Don’t lose your accuracy by having carbon build up and close off the clearance required for the most accurate bullet release through a muzzle brake.” Note: Extra charges apply for neck-turning and neck expansion operations, or specialized cartridge-forming operations. Please call 205-461-4680 for special services pricing.
Muzzle Brake – Tax Break Special for AccurateShooter.com Readers
Now through April 17, 2012 (Tax Due Date), Darrell is offering a Muzzle Brake – Tax Break Special for our readers. For all case prep/restoration orders of $50.00 or more, Darrell will ultrasonically clean one or two stainless muzzle brakes for no extra charge (offer does not apply to blued or coated muzzle brakes). For more info, visit DJsBrass.com or call Darrell Jones at 205-461-4680. IMPORTANT: Contact Darrell for shipping instructions BEFORE sending any brass for processing. ALL BRASS MUST BE DE-PRIMED before you send it.
Darrell has cleaned and annealed cases for shooters from across the country. Here are recent testimonials (this Editor reviewed all the original emails so I can confirm these are real):
“Your services were good with a quick turn-around time. Quality of the case annealing looked great[.]” — Tom, in Alaska
“The [300 Win Ackley] batch you did for me came back looking great.” — Chuck, in Arizona
“Since I started using Lapua brass, I’ve gotten gotten enough reloads out of them to notice that the necks were no longer sealing as well as I’d like. A friend suggested annealing them. I remembered seeing DJ’s ad on AccurateShooter.com and thought I’d give him a try. Not only did my [.308 brass] come back sorted exactly as I had sent them out, all had been so thoroughly cleaned that I realized I had been leaving lube on them after forming. DJ had taken the time to enclose a note cautioning me to brush the inside case necks and do a full-length resize for the first loading. And all 200 cases were back in my hands in DAYS, not weeks! Great service, great price, great follow up.” — Jim, in Alabama
When your cases become hard to extract, or you feel a stiff bolt lift when removing a cartridge, it’s probably time to full-length size your cases, and “bump” the shoulder back. With a hunting load, shoulder bumping may only be required every 4-5 loading cycles. Short-range benchrest shooters, running higher pressures, typically full-length size every load cycle, bumping the shoulder .001-.002″. High Power shooters with gas guns generally full-length size every time, and may need to bump the shoulders .003″ or more to ensure reliable feeding and extraction.
Use Shims for Precise Control of Shoulder Bump
Some shooters like to set the “default” position for their full-length die to have an “ample” .003″ or .004″ shoulder bump. When they need less bump, a simple way to reduce the amount of shoulder movement is to use precision shims in .001″ (one-thousandth) increments.
Mats Johansson writes: “I’ve been using [shims] since Skip Otto (of BR fame) came out with them. I set up my dies with the .006″ shim, giving me the option of bumping the shoulder a bit more when the brass gets old and hardens while still having room to adjust up for zero headspace, should I have missed the original setup by a thou or two. Hunting rounds can easily be bumped an extra .002-.003″ for positive, no-crush feeding. Being a safety-oriented cheapskate, I couldn’t live without them — they let me reload my cases a gazillion times without dangerous web-stretching. Shims are a must-have, as simple as that.”
Sinclair Int’l offers a 7-piece set of Die Shims that let you adjust the height of your die (and thereby the amount of bump and sizing) in precise .001″ increments. Sinclair explains: “Some handloaders will set their die up to achieve maximum sizing and then progressively use Sinclair Die Shims between the lock ring and the press head to move the die away from the shellholder. Doing this allows you to leave the lock ring in the same position. These shims are usually available in increments of .001″ and work very well.”
Seven Shims from .003″ to .010″
Sinclair’s $12.49 Die Shim Kit (item 22400) includes seven shims in thicknesses of .003, .004, .005, .006, .007, .008, and .010. For ease of use, shim thickness is indicated by the number of notches cut in the outer edge of each shim. Even without looking you can “count” the notches by feel.
Here 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.”
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….
We are often asked: “What size neck bushing is best for Lapua 6mmBR brass in a ‘no-turn’ chamber?” The questioner planned to purchase a Redding Type ‘S’ full-length sizing die with neck bushings. The quick answer is that one should probably get both 0.265 and 0.266 bushings and see what works best. With the current “blue box” Lapua brass, a loaded 6BR round with an unturned neck will typically run about 0.268″ (depending on the bullet). A 0.266″ neck bushing, after springback, will give about 0.0015″ tension which can work well in a bolt gun. In a gas gun, we recommend running .003″ (or more) neck tension.
Alternative to Bushings — Honed Full-Length dies
Conventional, non-bushing full-length sizing dies can create ultra-accurate ammo with very low run-out. For some applications, we prefer a non-bushing FL die over a bushing die — so long as the neck tension is correct. But many FL dies have an undersized neck diameter so you end up with excess neck tension, and you work the brass excessively. Forster offers a simple, inexpensive solution — honing the neck diameter to whatever size you want.
If you purchase a Forster non-bushing, full-length sizing die, Forster will hone the neck dimension to your specs for about $10.00 extra. This way you can have a FL die that provides the right amount of tension for your particular load. Forster dies are relatively inexpensive so you can afford to have a couple of FL dies with necks honed to different diameters — such as 0.265″ and 0.266″ for a no-turn 6mmBR. The die itself is very affordable — currently Sinclair Int’l charges $33.95 for a Forster 6mmBR full-length sizing die (item FP6BRFL).
Forster FL dies, necks honed to .265″, .266″, and .267″.
Steve Rasmussen of IowaHighPower.com gave this a try. In fact, he had three dies made — each with a different neck dimension. Here’s his report: “My original Forster 6BR FL die sized the necks down a lot, less than 0.260″, .256″ if I recall correctly. I sent my die in and asked if they could supply two more FL dies (for three total) to have the necks honed to 0.265″, 0.266″, and 0.267″. The cost was $10 for my supplied die and $38.50 plus $10.00 honing fee for each additional die. Return shipping was $11.00 via USPS Priority Mail.”
The table below shows the neck diameter range of ten (10) sized cases using each die. Brass springback after sizing runs 1 to 1.3 thousandths. Steve was using the older, “brown box” Lapua brass with thicker necks so he needed the .267″ bushing. The older Lapua 6mmBR brass measures about 0.2695″ with bullet in place. Steve explained: “My loaded rounds are running 0.2697-0.2699 using [brown box] Lapua 6BR brass. So far the dies are working well. I sized 80 cases with the 0.266″ necked die. The shoulder is running 0.4582″ and 0.300″ up from the base is 0.4684″. I spun 20 of ‘em and 16 had a runout of one thousandth (0.001) and the other 4 at 1.5 thousandths (0.0015).” That shows that these honed Forster FL dies produce exceptionally straight sized cases.
by James Calhoon
(First Printed in Varmint Hunter Magazine, October, 1995)
In the course of talking to many shooters, it has become clear to me that the manufacturers of primers have done a less than adequate job of educating reloaders on the application of their primers. Everybody seems to realize that some primers are “hotter” than others and some seem to shoot better for them than others, but few reloaders know that primers have different pressure tolerances.
Primer Pressure Tolerance
When loading a .223 to the maximum, I was getting primer piercing before I reached case overloading. I don’t know what prompted me to try CCI 450s instead of the 400s which I had been using, but I did. Presto! No more piercing! Interesting!? A primer that has a hotter ignition and yet withstands more pressure! Thats when I decided that it was time to do a dissection of all primers concerned. The chart below shows my results.
By studying the numbers (Cup “A” thickness), one can see which primers in the small rifle sections should be more resistant to primer cratering and/or piercing. Primer cup diameters are all similar and appear to follow a specification, but check out the cup thickness in the small rifle primers (Dimension “A”). Some cups are quite a bit thicker than others: .025″ for CCI 450 vs. .0019″ for Fed 200. Large rifle primers all appear to have the same cup thickness, no matter what the type. (As a note of interest, small pistol primers are .017″ thick and large pistol primers are .020″ thick.)
If you are shooting a 22 Cooper, Hornet, or a Bee, the .020″ cup will perform admirably. But try using the .020″ cup in a 17 Remington and you will pierce primers, even with moderate loads.
Considering that cup thickness varies in the small rifle primers, it is obvious that primer “flatness” cannot solely be used as a pressure indicator.
Another factor which determines the strength of a primer cup is the work-hardened state of the metal used to make the primer cup. Most primers are made with cartridge brass (70% copper, 30% zinc), which can vary from 46,000 psi, soft, to 76,000 psi tensile strength when fully hardened. Note that manufacturers specify the hardness of metal desired, so some cups are definitely “harder” that others.
What does all this mean to the reloader? - Cases that utilize small rifle primers and operate at moderate pressures (40,000 psi) can use CCI 400, Federal 200, Rem 6 1/2, or Win SR. Such cases include 22 CCM, 22 Hornet and the 218 Bee. Other cases that use the small rifle primer can use the above primers only if moderate loads are used. Keep to the lower end of reloading recommendations.
- Cases that utilize small rifle primers and operate at higher pressures (55,000 psi) should use CCI 450, CCI BR4, Fed 205 and Rem 7 1/2.
- All the large rifle primers measured have the same thickness. Therefore choose based on other factors, such as accuracy, low ES/SD, cost, cup hardness, and uniformity.
Hope this clears up some primer confusion. If you want more information about primers, priming compounds, or even how to make primers, the NRA sells an excellent book called “Ammunition Making” by George Frost. This book tells it like it is in the ammo making industry.
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We ran a 6XC QuickLOAD simulation with 115gr bullets and H4350 powder. QuickLOAD predicted that the observed difference in case capacity can result in pressure differentials as much as 4,500 psi! In other words, if you switch from Norma 6XC brass to a lesser-capacity brass type, your pressures could rise 4,500 psi (using H4350 and 115gr bullets).
Successful long-range shooters know that careful weighing of powder charges helps them achieve superior long-range accuracy. By maintaining powder charges within very narrow weight tolerances, hand-loaders can produce ammo with more consistent muzzle velocities from shot to shot. Low Extreme Spread (ES) and Standard Deviation (SD) numbers translate directly to reduced vertical dispersion at very long ranges (although velocity is not the only contributing factor to vertical spread). In pursuit of load weight uniformity, many of our top long-range aces have invested in the latest, high-tech 
For a reloader looking to achieve “perfect” load weight uniformity, powder kernel uniforming offers the ultimate control over powder weight. The method we devised to uniform individual kernels consists of kernel core-drilling. The propellant we chose for this kernel-uniforming test was a new prototype (not yet commercially available) EuroChemie RL “X” propellant. This was chosen because it offered relatively large, can-shaped kernels that could be drilled relatively easily.
Core-Drilling Kernels with Micro Drill-Bits
Proof That It Works
The Sinclair Stainless Ultimate Trimmer comes with Sinclair Mounting Stand and handy Shark Fin Clamp. This system makes easy work of installing and removing your trimmer case holder in a smooth “swing-arm” motion. The Shark Fin trimmer clamp secures the case head firmly against the micrometer adjustment head for a quick and accurate, chatter-free trim. NOTE: We have found that you will get the most accurate, repeatable trim lengths if you set the shark fin to a firm tension and do NOT hold the case-holder with your hand — let the Shark Fin clamp do the job. The video below shows how to use a Wilson case trimmer (with micrometer, stand and Shark Fin).
After just a few minutes spent learning the program’s tool buttons, we were able to plot shot groups on a variety of targets with ease. Once you select the target distance and bullet diameter, figuring group size is a simple matter of centering a circle tool over each bullet hole. Then the program “connects the dots” and provides all the info you could want automatically.
Here’s a tip that can help you score higher at matches and get more predictable results when weighing loads with an electronic scale. Kelly Bachand, a top prone shooter and electrical engineering major at the Univ. of Washington, tells us that all digital scales can drift. Therefore Kelly recommends re-calibrating electronic scales often. In addition — and this is key — Kelly recommends that you shoot the ammo in the exact order in which it was loaded. Arrange your loaded ammo in a box in the order of loading and shoot it first-loaded to last-loaded. (Or, if you prefer, shoot it last-loaded to first-loaded.) The important thing is to maintain the order and not mix everything up. That way, if your scale drifts, the effect of drift on charge weight will be incremental from one loaded round to the next, so point of impact change should be negligible. Conversely, if you shoot your last-loaded round right after your first-loaded round, the effect of scale drift is at its maximum, so powder charge varience is maximized. And that can produce a different point of impact (POI) on the target.
With the price of premium brass topping $90/100 for many popular cartridges, it makes sense to consider annealing your brass to extend its useful life. Forum member 
Here 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.
We are often asked: “What size neck bushing is best for Lapua 6mmBR brass in a ‘no-turn’ chamber?” The questioner planned to purchase a Redding Type ‘S’ full-length sizing die with neck bushings. The quick answer is that one should probably get both 0.265 and 0.266 bushings and see what works best. With the current “blue box” Lapua brass, a loaded 6BR round with an unturned neck will typically run about 0.268″ (depending on the bullet). A 0.266″ neck bushing, after springback, will give about 0.0015″ tension which can work well in a bolt gun. In a gas gun, we recommend running .003″ (or more) neck tension.
