Back in May, IBS shooter Rodney Wagner shot a 0.349″ (50-2X) 5-shot group that became the talk of the shooting community. This was the smallest 600-yard group shot in the history of recorded rifle competition. Rodney’s group cuts the existing IBS 600-yard record in half. Rodney put five shots under the size of a dime at the distance of six football fields. Just pause and think about that…
News of this amazing feat spread like wildfire via the internet. People were amazed at what Rodney accomplished. Here are some actual comments posted on various shooting forums:
308Nut: Simply Astounding.
Coues Sniper: That’s insanity.
PapaJohn: I strut around like a peacock if my rifles will shoot under a half-inch at 100 yards. His group was better than that at six times the distance… that’s just unfathomable. I don’t see anyone breaking that record for a loooooooooooong time!
Given the spectacular (and historic) nature of Rodney’s 600-yard group, many folks wanted to learn more about Rodney’s equipment and his shooting techniques. For that reason, we’ve compiled this follow-up report. Rodney was kind enough to provide a short video showing his equipment and shooting technique. In his video demonstration, Rodney runs off a 5-shot group in about 19 seconds. When he actually shot the 0.349″ group, Rodney estimates he got the five shots down-range in 12-15 seconds. (He slowed down a bit for the video!)
Watch Rodney Wagner Fire Five Shots in Under 20 Seconds
Rodney comments: “You’ll notice I hold the stock with my left hand while working the bolt to keep it from losing its ‘track’ (that slows me down a lot). I have just gotten into the habit of doing that because I feel tracking is one of the most important things not to take for granted. With this technique I don’t have to ‘saw’ the stock into the bags as much when I get on to the record target.”
Record-Setting Load: Varget Powder, CCI Primers, and Berger 108s Jumped
Rodney’s record 0.349″ group works out to 0.055 MOA at 600 yards. To shoot a “zero” group at 600 yards you need the finest components and insanely good reloading techniques (not to mention the grace of God.) As he does with all his 600-yard ammo, Rodney pre-loaded before the match. This particular ammo had been loaded 5-6 days before the match. Here are specs on Rodney’s load:
32.5 Grains of Hodgdon Varget Powder and CCI 450 Primers.
108gr Berger BT Match bullets seated 0.020″ away from the lands.
Lapua 6mmBR brass fire-formed to 6 Dasher and turned to 0.265″ loaded round for a 0.268″-neck chamber.
Neck-sized with a 0.262″ Redding bushing.
Note that Rodney was using Berger 108s, not the 105gr VLDs or Berger’s popular 105gr Hybrids. Rodney found his Brux barrel shot best with the 108s: “I’d get really nice 4-shot groups with the VLDs, but it seemed there would be four together and one out. The 108s seem to have less fliers.” Rodney experimented with seating depths before he settled on a .020″ jump: “I shot them for a long time 3 to 5 thousandths in the lands, just barely in the lands. But I knew Sam Hall had really good luck jumping. So I went to .020″ jump and it all came together. The 108s have shot good like that in three different Brux barrels (all chambered with the same reamer) so I just start at that setting now — twenty off the lands.”
Record-Setting Equipment
Rodney was shooting a 17-lb Light Gun. It features a BAT Machine ‘B’ action, and a 29″ Brux barrel chambered for the 6mm Dasher with a 0.268″ neck. The 0.236″-land, 4-groove barrel was fairly new when the record group was shot — it had about 300 rounds through it, and had shot 30 rounds since its last cleaning. Rodney chambered the barrel himself. The stock is a Shehane ST-1000 fiberglass tracker, inletted and bedded by Tom Meredith. A March 10-60x52mm scope is held in Burris Signature Zee rings on a +10 MOA rail. These rings are inexpensive, but they work just fine, notes Rodney: “With the inserts I can align the scope mechanically and keep the windage pretty much centered in its travel.”
Supporting his rifle, Rodney used a Farley co-axial rest up front (on Super-Feet) and a Protektor Doctor bag in the rear. The Farley features a Borden top carrying an Edgewood bag. Rodney notes: “In the front, I use the black diamond blasting sand, because it doesn’t pack as hard as regular sand. You can buy it at tractor supply stores in the welding section. It’s not as heavy as heavy sand.”
In the rear, Rodney runs a flat-top Protektor Doctor bag with Cordura ears. Rodney uses Sinclair heavy sand in his rear bag. He says “it’s got some squish — not much but just a little — call it a medium-hard fill”. Interestingly, Rodney sets up the bag so that the flat on the bottom of the stock rides on the stitches between the ears: “I like the stock to touch the top of the bag between the ears — I don’t like to see daylight.”
Conditions for the Record — You May Be Surprised
Many folks who have commented on Rodney’s 0.349″ group have wrongly assumed that the 0.349″ group was shot in “perfect” zero-wind conditions. Not so. There were switchy 5 mph winds with gusts to 10 mph. Rodney notes that on his second target of the day, he had to hold in three different places to manage a decent-sized group. So for those who think the group was shot in miraculous conditions, we have to say that wasn’t the case.
Creating Ultra-Accurate 6mm Dasher Ammunition
Rodney takes great care in loading his brass, and he employs a few tricks to get superior consistency.
Fire-Forming — To prepare his cases for fire-forming, Rodney starts by turning his Lapua brass to just past where the new neck-shoulder junction will be: “I just cut enough for the 6mm Dasher neck. A little bit of the cut shows on the shoulder after forming.” Then Rodney runs a .25-caliber K&M mandrel through the whole neck, expanding the neck diameter. After the entire neck is expanded, Rodney re-sizes the top section with a Wilson bushing, creating a false shoulder. Then, as further insurance that the case will be held firmly in place during fire-forming, Rodney seats his bullets long — hard into the lands. When fire-forming, Rodney uses a normal 6mmBR load of 29.8 grains of Varget: “I don’t like to stress my brass before it has been hardened. I load enough powder to form the shoulder 95%. Any more than that is just wasted.” Rodney adds: “When fire-forming, I don’t want to use a super-hard primer. I prefer to use a Federal 205, CCI 200, or Winchester — something soft.” Using a softer primer lessens the likelihood that the case will drive forward when hit by the firing pin, so this helps achieve more consistent “blow lengths”.
Ammo Loading — Rodney is fastidious with his brass and weighs his charges very precisely. Charges are first dispensed with an RFD manual powder measure, then Rodney trickles kernel by kernel using a highly-precise Sartorius GD-503 laboratory scale. He tries to maintain charge-weight consistency within half a tenth of a grain — about two kernels of Varget powder.
One important technique Rodney employs is sorting by bullet-seating force. Rodney batch-sorts his loaded rounds based on seating force indicated by the dial gauge on his K&M arbor press: “I use a K&M arbor press with dial indicator strain gauge. When I’m loading I pay lots of attention to seating effort and I try to batch five rounds that feel the same. For record rounds I try to make sure I get five of the same number (on the dial). When sorting based on the force-gauge readout, you need to go slow. If you go too fast the needle will spike up and down before you can see it.”
In practice, Rodney might select five rounds with a gauge value of 25, then another five with a gauge read-out of 30 and so on. He places the first five like-value rounds in one row of his ammo caddy. The next like-value set of five will go in the next row down. By this method, he ensures that all five cartridges in a five-round set for a record target will have bullets seated with very consistent seating force.
Unlike some top shooters, Rodney does not regularly anneal his cases. However, after every firing, he does tumble his Dasher brass in treated corncob media. After sizing his brass, before seating the bullets, he runs a nylon brush in the necks: “The last thing I do before firing is run a well-worn 30 caliber nylon brush in the necks, using a small 6-volt drill for power. This is a quick operation — just in and out the neck”. Sometimes, at the end of the season, he will anneal, but Rodney adds: “If I can get 10 firings out of the case I’ve done good.” He usually makes up new brass when he fits a new barrel: “If it is a good barrel (that I may shoot at the Nationals), I’ll usually go ahead and prepare 200 pieces of good brass.”
Shooting Techniques — Piloting a 600-yard Group into the Zeros Gun-handling and Rate of Fire — As you can see from the video, Rodney shoots with very minimal contact on the rifle. He normally shoots a string fast, but he remains calm and steady — almost machine-like. In the video he runs five shots in about 19 seconds, but he figures he shot the 0.349″ group in 12-15 seconds. Rodney says: “I’m not quite as fast as Sam Hall but I can usually run ‘em under fifteen seconds, sometimes closer to 10 on a good day. But when I shot the 0.349″ I couldn’t see the flags for the last shot so I dipped the joystick down between 4th and 5th shots, and that took a couple seconds. The flags had not changed, so I kept the same point of aim for 4th and 5th shot. I’d been watching that flag all morning, so to satisfy my curiosity I kind of dipped down for a second.”
Aiming for the Nine — To shoot ultra-small at long range, you must aim very, very precisely. When shooting at 600 yards, Rodney lines up his cross-hairs on the white number “9” in the blue field above the ten ring. This is visible through his rifle-scope at 600 yards, and it provides an aim point smaller than the center “X”.
Rodney explains: “I always aim for the number 9 up in the blue field. It provides for a smaller aim point. I noticed a difference when I started doing that. I learned that from some guys from South Dakota. It made sense so I’ve been doing it ever sense.”
Tips for 600-Yard Shooters New to the Game
In the course of our interview with Rodney, we asked if he had any tips for shooters who are getting started in the 600-yard Benchrest Game. Rodney offered some sensible advice:
1. Don’t try to go it alone. Find an old-timer to mentor you. As a novice, go to matches, watch and ask questions.
2. Go with a proven cartridge. If you are shooting 600 yards stick with a 6mmBR or one of the 6BR improveds (BRX or Dasher). Keep it simple. I tried some of the larger cartridges, the 6XC and 6-6.5×47 Lapua. I was trying to be different, but I was not successful. It wasn’t a disaster — I learned something. But I found the larger cases were not as accurate as a 6BR or Dasher. Those bigger cartridges are competitive for score but not for group.
3. You don’t have to spend a fortune to be competitive. Buy a used rifle from somebody and find out if you like the sport. You can save a lot with a used rifle, but do plan on buying a new barrel immediately.
4. Don’t waste weeks or months struggling with a barrel that isn’t shooting. My best barrels, including this record-setting Brux, started shooting exceptionally well right from the start.
Precision Reloading is having a June SALE on big-name reloading presses and powder dispensers. You’ll find good values on Redding, RCBS, Lyman, and Hornady Products. This special sale ends June 30, 2013. Note: Sale pricing is limited to quantities on hand and the discount prices cannot be combined with any other offers or promotions.
RCBS Cash-Back Rebate
In addition, RCBS is offering a Rebate for products purchased in 2013. If you buy $50 worth of RCBS hardware you can get $10 Cash Back. If you buy $300 worth of RCBS equipment you can get $50 Cash Back.
NOTE: Although the Rebate Form refers to an option of Speer Bullets (instead of cash money), due to shortages, ALL rebates will be issued in CASH. CLICK HERE for Rebate Form.
How would you like to lower your Extreme Spread (ES) and Standard Deviation (SD) significantly by a simple procedure that takes seconds and costs almost nothing?
Here’s all you need to do. After lubing your cases for full-length sizing, be sure to clean your hands (removing ALL residual lube) before you handle your bullets. As an extra measure to avoid lube contamination, slip on thin Latex gloves before you handle and seat your bullets. Will this make a difference? Let me tell you a story.
Keep Those Greasy Fingers Off Your Bullets
I recently loaded a couple dozen cases for a 6mm Dasher. We were in a hurry to leave for the range so I was loading faster than normal. When we started shooting the ammo I noticed that the 5-shot ES was bad — really bad — 48 fps. I was shocked because this was a known good load that had previously showed ES in the teens. This one had me stumped. What could have resulted in this high ES? What did I do different while reloading this time?
Then a lightbulb went off. I realized I had been seating bullets (round by round) immediately after lubing and sizing each case. My fingers still had some greasy lube on them which obviously got on some of the bullets, “polluting” them. My normal reloading procedure is to lube and size all cases, clean them off, then place the brass in a loading tray. Then I would clean my hands BEFORE adding powder and seating bullets. This time, in my rush, I sized a case, wiped it off, then immediately added powder and projectile. I did not take the time to clean off my fingers carefully before handling the bullets.
Big Drop in ES When I Avoided Bullet Contamination with Case Lube
The next day I went back to the loading room. I loaded the same brass with the same powder, same primer, same bullet type, same bushing — same everything. But this time, I washed my hands thoroughly with a hand cleaner, dried them with a clean paper towel, and I even put on thin latex gloves before handling the bullets. I loaded 10 rounds and fired them over the chronograph again in the same rifle. The 5-shot ES was 14 fps and the 10-shot ES was 22 fps (That’s normal for this load/rifle). Compare that to a 5-shot ES of 48 the day before. I had reduced my 5-shot ES by 70%! We were back in business. (By the way, the groups were also very small).
Lesson Learned — Keep Case Lube Off Your Bullets Your results may vary of course, but now I always make sure to remove ALL residual lube from my fingers before handling bullets or doing anything that can get unwanted lube inside the necks.
What about gloves? I don’t think the Latex gloves are essential (if your hands are dry and clean), but they just cost a few pennies when bought in bulk. You can buy a box of 100 latex gloves for under $7.00 on Amazon.com. I suggest the non-powdered type.
Use Your Common Sense
Before the critics launch a tirade, let me be the first to acknowledge that many champions have loaded perfectly good ammo (and shot great groups) without paying much attention to greasy fingers. We’ve all seen short-range benchresters loading ammo between relays. They work fast and may not take the time to clean all lube off their fingers before seating bullets. And we’ve seen some of those guys go out and shoot itty-bitty groups in the ones and zeros. So I am NOT claiming that careful “reloading bench hygiene” is essential to shooting small!
All I am saying is that I observed and recorded a significant drop in my ES when I made sure to avoid contaminating bullet jackets with case lube. This is a simple precaution that is easy to follow when loading at home. It may help you cut your ES/SD. It may help avoid that one “mystery flyer” that ruins a group. Cleaning your hands before seating bullets may seem obsessive. But the smart reloader knows that paying attention to the small details, in all respects, is the key to making ultra-accurate ammo that exhibits low ES/SD on the chronograph.
The 6mm Dasher is based on the 6mm BR cartridge with the shoulder blown forward about 0.100″ and “improved” to 40°. Case capacity is raised to about 41.0 grains. This allows the Dasher to drive 105-108gr bullets comfortably at 2970-3000 fps without over-stressing the brass. A popular load used by many successful Dasher shooters is 32.5 to 33.0 grains of Reloder 15, CCI 450 primers, with 105gr Berger VLDs, .010″ in the lands, or Berger 105gr Hybrids .015-.020″ off the lands (jumping). At the upper end this is a “warm load” and should only be used with fire-formed brass. Norma 203B is very, very similar to Reloder 15, and may be more readily available in the near future. As with any load, start 10% low and work up.
You may also have good luck with Hodgon Varget powder. Forum Member Rodney Wagner recently shot a spectacular IBS-record-setting 0.349″ five-shot group at 600 yards. Rodney was loading 32.5 Grains of Varget with CCI 450 primers and Berger 108gr BTs seated about .020″ off the lands (jumping). In preparation for fire-forming his Dasher cases, Rodney used a .257 expander to create a false shoulder on his case necks. This helps stabilizes the case with a good “crush fit” when fire-forming, but other methods of forming Dasher cases (including hydro-forming) can work well also.
Robert Hoppe, one of the top 600-yard shooters in the country, was the 2009 NBRSA 600-yard champion. In 2007, shooting a 6 Dasher, Robert nailed a 0.5823″, 5-shot group. At the time it was the smallest group ever shot in 600-yard registered benchrest competition. In 2008, John Lewis shot even smaller with an IBS Heavy Gun, but Robert’s 0.5823″ still remains the NBRSA 600-yard record, and we believe it is the second smallest group ever shot at 600 yards (in registered BR competition) by a 17-lb class rifle. Robert has been very successful in the 600-yard game, and is one of the best 600-yard shooters in the West. He knows how to wring the best accuracy out of the 6mm Dasher cartridge. Here Robert offers some tips on load development and tuning for the 6mm Dasher.
Our IT guy, Jay (aka JayChris in the Forum), was having some issues with his .260 AI. A load with known accuracy had suddenly and mysteriously stopped shooting well. Jay couldn’t figure out what was going wrong. Then he remembered he had cleaned his brass using a powerful ultrasonic machine.
He inspected his brass carefully and saw that the ultrasonically-cleaned necks were so “squeaky clean” that he was actually scratching the jackets on his bullets when seating them. As well, Jay noticed that it took more force to seat the bullets and the seating force became less uniform case to case. Jay solved the problem by applying NECO Moly dry-lube inside the necks of his brass before seating the bullets.
The Perils of Ultrasonic Brass Cleaning by JayChris
I rotate my brass so that I can keep track of each firing, so I keep a “clean/ready to load” bin and a “fired” bin. I have 400 pieces of .260 AI brass. So, all of it was on its first firing (after doing a Cream of Wheat fire-forming) until I hit the 400-round mark. To my surprise, things went south at the 500-round mark. The first time I noticed it (according to my range log) was at a match last year, when I dropped several points and had some vertical stringing issues. After that match, I had 400 rounds through the barrel and all of my brass had a single firing on it. So, it was time to clean.
I have used an ultrasonic cleaner for a while now. I recently got a more powerful Ultrasonic cleaner, although I don’t know if that makes a difference. My brass comes out dry and squeaky. Emphasis on the “squeaky”.
I found that my new US machine may have been getting the necks TOO clean. After ultrasonically cleaning my brass, I had noticed that it required a little more force to seat the bullets, but I didn’t really think too much about it. But then, after going over my ordeal with a shooting buddy and going over my process in minutiae, we had an “AH HA” moment when it came to cleaning (he uses good ol’ vibratory cleaning).
So, I used some moly dry-lube to pre-lube the case necks and took some rounds out to test at 200 yards. I used my last known good load and sure enough, the vertical flyers disappeared! I shot two, 10-rounds groups with .335 and .353 MOA vertical dispersion, which is consistent with the results I was originally getting.
Other folks have suggested necks may get “too clean” after ultrasonic cleaning. It was pretty sobering to actually witness, first hand, what can happen when brass is “too clean”. I had read some discussions of issues with neck friction/bullet seating after ultrasonic cleaning, but, frankly, I dismissed the idea. Now I understand. The “too clean” effect doesn’t seem to affect my Dasher at all (perhaps because Dasher necks are very short), but on the bigger .260 AI, it definitely does.
Close-Up Photos of Case-Necks
Here are photos Jay took with a microscope. You can see the difference between tumbled brass and ultrasonically-cleaned brass. Jay says: “Here, in sequence, are the Ultrasound-squeaky-clean case neck, a case neck after treatment with NECO moly dry-lube (you can see the particles that will help coat the neck during seating), and, finally, the neck from a case cleaned with corncob media in a vibratory tumbler. You can clearly see how much smoother the inside of the tumbled neck is. Yes, it’s dirty, but it’s also very, very smooth.
Close-Up of Scratched Bullet
Here is a close-up of a bullet that was seated in an ultrasonically-cleaned (“squeaky clean”) neck, with no lubrication. You can clearly see the damage done to the jacket — in fact, in a couple spots you can see the lead core through the scratches! Jay also observed that quite a bit more seating force was required to seat the bullet in a “squeaky clean” neck.
NOTE: The bullet jacket is naked — NOT coated in any way. It looks a little dark because of the shadow from the microscope lens, and the high contrast.
We often get questions about the 6.5 Creedmoor Cartridge — folks ask where they can find good resources for this cartridge, which is popular with Across-The-Course, High Power, and tactical shooters. We did some searching and found that the August 2011 digital edition of Shooting Sports USA has a good article for all fans of the 6.5 Creemoor.
Development of the 6.5 Creedmoor Cartridge
In the August 2011 Edition of Shooting Sports USA you’ll find a lengthy feature on the 6.5 Creedmoor cartridge. This story covers the origin of the cartridge and its performance both as a match cartridge and as a hunting round. Hornady Chief Ballistician Dave Emary explained: “the original intent of the cartridge was as an across-the-course match cartridge. We envisioned it as an off-the-shelf round that would produced the accuracy and ballistics to compete in all match disciplines right out of the box. At the same time we realized that the same characteristics would make an exceptional hunting cartridge with the right bullets.”
6.5 Creedmoor Brass No Longer Washed After Annealing
Here’s an interesting update on Hornady 6.5 Creedmoor brass and loaded ammo. In a move to improve case quality and neck uniformity, Hornady recently changed the 6.5 Creedmoor production process, eliminating the case-washing step after annealing. So now you will see annealing coloration on 6.5 Creedmoor brass, just like on Lapua brass. Dennis DeMille of Creedmoor Sports wanted to improve the consistency/uniformity of 6.5 Creedmoor case-necks. At Dennis’ suggestion, Hornady conducted tests which showed that the “standard industry practice” of washing brass could potentially alter the necks in undesirable ways. Bottom line, unwashed annealed brass was determined to have an accuracy edge over washed brass. Looking at these results, Hornady decided to forgo the post-anneal washing process. As a result, the latest 6.5 Creedmoor brass now displays the distinctive coloration left by neck/shoulder annealing. Learn something new every day, eh?
Effects Of Cartridge Over All Length (COAL) And Cartridge Base To Ogive (CBTO) – Part 1 by Bryan Litz forBerger Bullets.
Many shooters are not aware of the dramatic effects that bullet seating depth can have on the pressure and velocity generated by a rifle cartridge. Cartridge Overall Length (COAL) is also a variable that can be used to fine-tune accuracy. It’s also an important consideration for rifles that need to feed rounds through a magazine. In this article, we’ll explore the various effects of COAL, and what choices a shooter can make to maximize the effectiveness of their hand loads.
Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI)
Most loading manuals (including the Berger Manual), present loading data according to SAAMI (Sporting Arms and Ammunition Manufacturers’ Institute) standards. SAAMI provides max pressure, COAL and many other specifications for commercial cartridges so that rifle makers, ammo makers, and hand loaders can standardize their products so they all work together. As we’ll see later in this article, these SAAMI standards are in many cases outdated and can dramatically restrict the performance potential of a cartridge.
Bullet seating depth is an important variable in the accuracy equation. In many cases, the SAAMI specified COAL is shorter than what a hand loader wants to load their rounds to for accuracy purposes. In the case where a hand loader seats the bullets longer than SAAMI specified COAL, there are some internal ballistic effects that take place which are important to understand.
Effects of Seating Depth / COAL on Pressure and Velocity
The primary effect of loading a cartridge long is that it leaves more internal volume inside the cartridge. This extra internal volume has a well known effect; for a given powder charge, there will be less pressure and less velocity produced because of the extra empty space. Another way to look at this is you have to use more powder to achieve the same pressure and velocity when the bullet is seated out long. In fact, the extra powder you can add to a cartridge with the bullet seated long will allow you to achieve greater velocity at the same pressure than a cartridge with a bullet seated short.
Figure 1. When the bullet is seated farther out of the case, there is more volume available for powder. This enables the cartridge to generate higher muzzle velocity with the same pressure.
When you think about it, it makes good sense. After all, when you seat the bullet out longer and leave more internal case volume for powder, you’re effectively making the cartridge into a bigger cartridge by increasing the size of the combustion chamber. Figure 1 illustrates the extra volume that’s available for powder when the bullet is seated out long.
Before concluding that it’s a good idea to start seating your bullets longer than SAAMI spec length, there are a few things to consider.
Geometry of a Chamber Throat
The chamber in a rifle will have a certain throat length which will dictate how long a bullet can be loaded. The throat is the forward portion of the chamber that has no rifling. The portion of the bullet’s bearing surface that projects out of the case occupies the throat (see Figure 2).
The length of the throat determines how much of the bullet can stick out of the case. When a cartridge is chambered and the bullet encounters the beginning of the rifling, known as the lands, it’s met with hard resistance. This COAL marks the maximum length that a bullet can be seated. When a bullet is seated out to contact the lands, its initial forward motion during ignition is immediately resisted by an engraving force.
Seating a bullet against the lands causes pressures to be elevated noticeably higher than if the bullet were seated just a few thousandths of an inch off the lands.
A very common practice in precision reloading is to establish the COAL for a bullet that’s seated to touch the lands. This is a reference length that the hand loader works from when searching for the optimal seating depth for precision. Many times, the best seating depth is with the bullet touching or very near the lands. However, in some rifles, the best seating depth might be 0.100″ or more off the lands. This is simply a variable the hand loader uses to tune the precision of a rifle.
Conventional .308 Winchester brass has a large primer pocket with a large, 0.080″-diameter flash hole. In 2010, Lapua began producing special edition .308 Win “Palma” brass that has a small primer pocket and a small flash hole, sized 1.5mm (.059″) in diameter. Tests by U.S. Palma Team members showed that the small-flash-hole .308 brass possibly delivers lower Extreme Spread (ES) and Standard Deviation (SD) with some bullet/powder/primer combinations. All things being equal, a lower ES should reduce vertical dispersion at long range.
Why Might a Small Flash Hole Work Better?
The performance of the small-flash-hole .308 brass caused some folks to speculate why ES/SD might be improved with a smaller flash hole. One theory (and it’s just a theory) is that the small flash hole creates more of a “jet” effect when the primer fires. German Salazar (Rifleman’s Journal Editor) sought to find out, experimentally, whether this theory is correct. German explained: “During one of the many internet forum discussions of these cases, Al Matson (AlinWA) opined that the small flash hole might cause the primer flash to be propagated forward more vigorously. In his words, it should be like shooting a volume of water through a smaller nozzle, resulting in a flash that reaches further up the case. Now that kind of comment really sparked my curiosity, so I decided to see what I could see.”
More Primer Testing by Salazar
You can read more about this test and other primer experiments on RiflemansJournal.com.
Large and Small Flash Hole .308 Cases — But Both with Small Primer Pockets
To isolate the effect of flash hole diameter alone, German set up a test with the two types of .308 case that have a small primer pocket: Remington BR brass with a 0.080″ flash hole and Lapua Palma brass with a 0.062″ flash hole. NOTE: German reamed the Lapua brass to 0.062″ with a Sinclair uniforming tool, so it was slightly larger than the 0.059″ factory spec. The Remington brass has a .22 BR headstamp as this brass was actually meant to be re-formed into .22 BR or 6 BR before there was factory brass available for those cartridges.
German set up his primer testing fixture, and took photos in low light so you can see the propagation of the primer “blast” easily. He first tested the Remington 7 1/2 primer, a primer known for giving a large flame front. German notes: “I thought that if there was a ‘nozzle effect’ from the small flash hole, this primer would show it best. As you can see from the photos, there might be a little bit of a flash reduction effect with this primer and the small flash hole, the opposite of what we expected, but it doesn’t appear to be of a significant order of magnitude.”
Next German tested the Wolf .223 primer, an unplated version of the Small Rifle Magnum that so many shooters use. German notes: “This is a reduced flame-front (low flash) primer which has proven itself to be very accurate and will likely see a lot of use in the Lapua cases. With this primer, I couldn’t detect any difference in the flash produced by the small flash hole versus the large flash hole”.
Remington BR case, 0.080″ Flash Hole, Wolf .223 Primer.
Palma case, 0.062″ Flash Hole, Wolf 223 Primer.
German tells us: “I fired five or six of each primer to get these images, and while there is always a bit of variance, these are an accurate representation of each primer type and case type. You can draw your own conclusions from all this, I’m just presenting the data for you. I don’t necessarily draw any conclusions as to how any combination will shoot based on the pictures.”
Results of Testing
Overall, looking at German’s results, one might say that the smaller diameter of the small flash hole does not seem to have significantly changed the length or size of the primer flame front. There is no discernible increased “jet effect”.
Cabelas.com has just made available some of the hard-to-find Hodgdon propellants, in 1-lb containers. H4831sc, Benchmark, H380, Hybrid 100V, Retumbo, H414 are all showing as “in stock” with prices ranging from $22.99 to $27.99 per pound, with a $20.00 HazMat fee. There is a catch — purchasers are limited to two (2) pounds of any Hodgdon powder product per order, per day. The 1-lb containers of H4831sc are currently on sale at $25.99, marked down from $27.99. NOTE: Varget was available earlier today at Cabelas.com, but Varget actually sold out minutes before this story was published. Good luck grabbing some of the other powders!
Readers who have just recently discovered the Daily Bulletin may not realize that AccurateShooter.com has hundreds of reference articles in our archives. These authoritative articles are divided into mutiple categories, so you can easily view stories by topic (such as competition, tactical, rimfire, optics, shooting skills etc.). One of the most popular categories is our Technical Articles Collection. On a handy index page (with thumbnails for every story), you’ll find over 100 articles covering technical and gunsmithing topics. These articles can help you with major projects (such as stock painting), and they can also help you build more accurate ammo. Here are five popular selections from our Technical Articles archive.
Stress-Free Pillar Bedding. Richard Franklin explains how to do a top-quality bedding job, start to finish.
OnTarget Software Review. Our Editors test free software that measures shot groups with great precision. We explain how to use the program and configure advanced features.
Savage Action Tuning. Top F-TR shooter Stan Pate explains how to enhance the performance of your Savage rifle by optimizing the torque settings of the action screws.
Complete Precision Case Prep. Jake Gottfredson covers the complete case prep process, including brass weight sorting, case trimming, primer pocket uniforming, neck-sizing, and, case-neck turning.
Stock Painting Instructions. Step-by-step guide for stock painting by expert Mike Ricklefs. Mike shows both simple coverage and fancy effects.
Back in May, IBS shooter Rodney Wagner shot a 0.349″ (50-2X) 5-shot group that became the talk of the shooting community. This was the smallest 600-yard group shot in the history of recorded rifle competition. Rodney’s group cuts the existing IBS 600-yard record in half. Rodney put five shots under the size of a dime at the distance of six football fields. Just pause and think about that…
One important technique Rodney employs is sorting by bullet-seating force. Rodney batch-sorts his loaded rounds based on seating force indicated by the dial gauge on his K&M arbor press: “I use a K&M arbor press with dial indicator strain gauge. When I’m loading I pay lots of attention to seating effort and I try to batch five rounds that feel the same. For record rounds I try to make sure I get five of the same number (on the dial). When sorting based on the force-gauge readout, you need to go slow. If you go too fast the needle will spike up and down before you can see it.”
Aiming for the Nine — To shoot ultra-small at long range, you must aim very, very precisely. When shooting at 600 yards, Rodney lines up his cross-hairs on the white number “9” in the blue field above the ten ring. This is visible through his rifle-scope at 600 yards, and it provides an aim point smaller than the center “X”.
How would you like to lower your Extreme Spread (ES) and Standard Deviation (SD) significantly by a simple procedure that takes seconds and costs almost nothing?
The 6mm Dasher is based on the 6mm BR cartridge with the shoulder blown forward about 0.100″ and “improved” to 40°. Case capacity is raised to about 41.0 grains. This allows the Dasher to drive 105-108gr bullets comfortably at 2970-3000 fps without over-stressing the brass. A popular load used by many successful Dasher shooters is 32.5 to 33.0 grains of Reloder 15, CCI 450 primers, with 105gr Berger VLDs, .010″ in the lands, or Berger 105gr Hybrids .015-.020″ off the lands (jumping). At the upper end this is a “warm load” and should only be used with fire-formed brass. Norma 203B is very, very similar to Reloder 15, and may be more readily available in the near future. As with any load, start 10% low and work up.
Our IT guy, Jay (aka JayChris in the Forum), was having some issues with his .260 AI. A load with known accuracy had suddenly and mysteriously stopped shooting well. Jay couldn’t figure out what was going wrong. Then he remembered he had cleaned his brass using a powerful ultrasonic machine.
I have used an ultrasonic cleaner for a while now. I recently got a more powerful Ultrasonic cleaner, although I don’t know if that makes a difference. My brass comes out dry and squeaky. Emphasis on the “squeaky”. 
6.5 Creedmoor Brass No Longer Washed After Annealing
Effects Of Cartridge Over All Length (COAL) And Cartridge Base To Ogive (CBTO) – Part 1
