We are often asked “Can I get more velocity by switching primer types?” The answer is “maybe”. The important thing to know is that changing primer types can alter your load’s performance in many ways — velocity average, velocity variance (ES/SD), accuracy, and pressure. Because there are so many variables involved you can’t really predict whether one primer type is going to be better or worse than another. This will depend on your cartridge, your powder, your barrel, and even the mechanics of your firing pin system.
BE SAFE: Glen Zediker recommends decreasing your load ONE FULL GRAIN when changing to a different primer type, one that you haven’t used before.
Interestingly, however, a shooter on another forum did a test with his .308 Win semi-auto. Using Hodgdon Varget powder and Sierra 155gr Palma MatchKing (item 2156) bullets, he found that Wolf Large Rifle primers gave slightly higher velocities than did CCI-BR2s. Interestingly, the amount of extra speed (provided by the Wolfs) increased as charge weight went up, though the middle value had the largest speed variance. The shooter observed: “The Wolf primers seemed to be obviously hotter and they had about the same or possibly better ES average.” See table:
Varget .308 load
45.5 grains
46.0 grains
46.5 grains
CCI BR2 Primers
2751 fps
2761 fps
2783 fps
Wolf LR Primers
2757 fps
2780 fps
2798 fps
Speed Delta
6 fps
19 fps
15 fps
You can’t extrapolate too much from the table above. This describes just one gun, one powder, and one bullet. Your Mileage May Vary (YMMV) as they say. However, this illustration does show that by substituting one component you may see significant changes. Provided it can be repeated in multiple chrono runs, an increase of 19 fps (with the 46.0 grain powder load) is meaningful. An extra 20 fps or so may yield a more optimal accuracy node or “sweet spot” that produces better groups. (Though faster is certainly NOT always better for accuracy — you have to test to find out.)
WARNING: When switching primers, you should exercise caution. More speed may be attractive, but you have to consider that the “speedier” primer choice may also produce more pressure. Therefore, you must carefully monitor pressure signs whenever changing ANY component in a load. Glen Zediker recommends decreasing your load ONE FULL GRAIN when changing to a different primer type, one that you haven’t used before.
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It’s July 4th, that means fireworks displays. What better time to order up some gunpowder? We’re pleased to report that Midsouth Shooters Supply has received some big shipments from the major powder makers. In stock now at Midsouth are many of the most popular accuracy powders, including: Hodgdon H4350, Hodgdon 4831/4831SC, IMR 4166, Vihtavuori N133, Accurate LT30 and LT32, Norma 203B, CFE223 and many more. Powder Valley also has Hodgdon H4350 right now.
Meanwhile at Precision Reloading you will find Alliant Reloder 16, Reloder 23, Reloder 17, IMR 4166, IMR 8208 XBR, Vihtavuori N133, Accurate LT30 and LT32, Norma 203B, and many more.
H4350 and Reloder 16 are superb, temp-stable powders for medium-sized cartridges. Reloder 23 is a slower version of RL16 that works great in magnum cartridges. LT30 is great for the 30BR, CFE 223 is excellent for Service Rifle shooters, and VV N133 is a top choice for the 6PPC. Norma 203B (nearly identical to Reloder 15) works well in the 6mmBR, 6BRA and Dasher. And Hodgdon H4831SC is an excellent choice for the .284 Winchester and 7mm WSM.
Sorry we could not find Hodgdon Varget at these two vendors. However, Bruno Shooters Supply does have Varget in stock today in both 1-lb and 8-lb sizes. Varget fans may also want to try IMR 8208 XBR. It has a slightly faster burn rate, but our tests found it worked very well in the .308 Win with medium-weight bullets, offering excellent accuracy and good velocity.
All these popular Powders (and many more) are in stock:
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Summer Solstice 2020 was June 20th, and July’s nearly here. That means “peak heat” summer conditions. It’s vitally important to keep your ammo at “normal” temps during the hot summer months. Even if you use “temp-insensitive” powders, studies suggest that pressures can still rise dramatically when the entire cartridge gets hot, possibly because of primer heating. It’s smart to keep your loaded ammo in an insulated storage unit, possibly with a Blue Ice Cool Pak if you expect it to get quite hot. Don’t leave your ammo in the car or truck — temps can exceed 140° in a vehicle parked in the sun.
To learn more about how ambient temperature (and primer choice) affect pressures (and hence velocities) you should read the article Pressure Factors: How Temperature, Powder, and Primer Affect Pressure by Denton Bramwell. In that article, the author uses a pressure trace instrument to analyze how temperature affects ammo performance. Bramwell’s tests yielded some fascinating results.
For example, barrel temperature was a key factor: “Both barrel temperature and powder temperature are important variables, and they are not the same variable. If you fail to take barrel temperature into account while doing pressure testing, your test results will be very significantly affected. The effect of barrel temperature is around 204 PSI per F° for the Varget load. If you’re not controlling barrel temperature, you about as well might not bother controlling powder temperature, either. In the cases investigated, barrel temperature is a much stronger variable than powder temperature.”
This Editor had the personal experience of 6mmBR hand-loaded ammo that was allowed to sit in the hot sun for 45 minutes while steel targets were reset. The brass became quite warm to the touch, meaning the casings were well over 120° on the outside. When I then shot this ammo, the bullets impacted well high at 600 yards (compared to earlier in the day). Using a Magnetospeed, I then chron-tested the sun-heated ammo. The hot ammo’s velocity FPS had increased very significantly — all because I had left the ammo out in the hot sun uncovered for 3/4 of an hour.
Powder Heat Sensitivity Comparison Test
Our friend Cal Zant of the Precision Rifle Blog recently published a fascinating comparison test of four powders: Hodgdon H4350, Hodgdon Varget, IMR 4451, and IMR 4166. The first two are Hodgdon Extreme powders, while the latter two are part of IMR’s Enduron line of propellants.
The testers measured the velocity of the powders over a wide temperature range, from 25° F to 140° F. Hodgdon H4350 proved to be the most temp stable of the four powders tested.
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Have you tried IMR Enduron powders yet (IMR 4166, 4451, 4955, and 7977)? We’ve been impressed with what we’ve seen. IMR’s line of Enduron extruded powders offer excellent temp stability, reduced copper fouling, and good load density for many popular cartridges (such as .223 Rem, 6mmBR, .308 Win, .30-06, 300 WSM to name a few). Some of our Forum members have reported excellent results with IMR 4166 in the 6mmBR, Dasher, 6.5×47 Lapua and .308 Win. One member wrote: “in my 6.5×47… 4166 gives speeds and accuracy pretty much exactly the same as Varget.” And other shooters have observed reduced copper fouling with Enduron series powders, so IMR’s Enduron anti-fouling chemistry does seem to work.
Varmint hunters, big game hunters, match shooters and military snipers all seek powders that are insensitive to temperature changes. These powders all have it. This translates to point of impact and group size remaining the same, no matter what temperature conditions prevail. Another huge benefit is an additive that prevents copper fouling from building during dozens of rounds being fired. Here the advantage is top accuracy for longer periods of time, and less cleaning time.
A third major accomplishment with this technology is ideal load density. Experienced reloaders know that a case-filling load often delivers the most uniform velocities and best accuracy. We see this in popular match cartridges such as the 6PPC, 6mmBR, 6BRA, 6.5 Creedmoor and .308 Win. These new Enduron powders offer excellent “full case” load density for the most commonly used cartridges with popular bullets.
These three powders, IMR 4166, IMR 4451 and IMR 7977, are environmentally friendly by not having any ingredients harmful to the environment. Add to that, the three of them cover the most popular cartridges from .204 Ruger up to the mighty 500 Nitro Express, and the handloader “has it all”.
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At the request of our readers, we provide select “Deals of the Week”. Every Sunday afternoon or Monday morning we offer our Best Bargain selections. Here are some of the best deals on firearms, hardware, reloading components, optics, and shooting accessories. Be aware that sale prices are subject to change, and once clearance inventory is sold, it’s gone for good. You snooze you lose.
1. Stocky’s — Long Range Composite Accublock Stocks, $219.99
Do you need an electronic powder scale and dispenser? Check out this great deal at Midsouth Shooters Supply. Suggested retail for the ChargeMaster Lite is $299.99 and most vendors are charging $289.99. But now you can get it for just $219.99 at Natchez. So you can save $70.00 with this sale! Put the money saved into bullets or powder. The RCBS ChargeMaster Lite is the modern second generation Scale/Dispenser, descended from the original ChargeMaster. The ChargeMaster Lite features an easy-to-use LCD touchscreen. Dispenser precision is plus/minus 0.1 grains. The unit comes with twin check weights and a convenient plastic cover for the powder pan.
3. CDNN Sports — Walther or S&W 9mm Pistol, Under $280.00
Here are two super deals on quality 9mm handguns. Both these double-stack pistols have 4″ barrels, 16-round capacity, and Picatinny rails in front. The Walther 9mm Creed offers quality German construction for $269.89. Or choose Smith & Wesson’s ergonomic, accurate SD9VE model for $279.99. The S&W’s weight, unloaded, is 22.7 ounces.
4. Powder Valley and Natchez — Varget and H4350 in Stock
Hodgdon’s Varget and H4350 are favorites of competition and tactical shooters. These powders are ideal for popular match calibers such as 6mmBR/Dasher (Varget) and 6mm Creedmoor (H4350). Being in high demand, these powders are often hard to find. But now Natchez Shooters Supply has Varget 1-pounders in stock for $29.99. Natchez also has H4350 in stock, as does Powder Valley Inc.(PVI). Powder Valley has H4350 in stock in both 1-lb ($28.15) and 8-lb ($201.00) containers. Get it while you can. Plus Powder Valley has Alliant Reloder 16 in stock (both 1-lb and 8-lb), a superb alternative if your rifle likes H4350.
5. EuroOptic — Nikon BLACK Riflescope Closeout Sale
If you’re in the market for a tactical scope, check out EuroOptic’s Nikon BLACK riflescope sale. These are good, reliable scopes that rival optics costing twice as much. EuroOptic has a good selection at prices up to 40% off. Choose MOA or MRAD versions with a variety of reticle options. NOTE: These BLACK Nikons are quality scopes that have performed well in the field. You’d have to pay hundreds more to do much better.
6. MidwayUSA — Pro Series Competition Shooting Mat, $34.99
The MidwayUSA Pro Series Competition Shooting Mat is now on sale for just $34.99, 36% off the basic price. The Pro Series mat measures a full 73.5″ x 35.5″. Zippered pockets on the front flap hold ammo or log books. And there are webbing “pockets” for bipod feet so you can pre-load your bipod with forward pressure. This quality mat boasts 0.35″ thick padding, multiple pockets, 6 grommets for staking, and a nice carry strap. It’s easy to transport, rolling up to about nine inches in diameter. User reviews of this $34.99 Shooting Mat have been very positive.
7. Amazon — Vinca Digital Caliper, $21.98
Every handloader needs a set of calipers, and this Vinca unit offers some great features for a very affordable price. Do you ever wish you could take measurements and record them easily for review later? Grab this Vinca Digital Caliper for only $21.98 and you can upload data as you measure. The unit features a RS232 data transfer port that can communicate to a windows laptop or computer with an accessory cable (sold separately). NOTE: The RS232 Data transfer port must connect with “VINCA DTCR-03″ Cable to make data transfer to PC. DO NOT CONNECT WITH REGULAR USB CABLE. This unit comes with one extra battery, and the maker offers a satisfaction guarantee.
8. Cabela’s — Huge Summer Sale, Save up to 40%
Dozens of items are on sale at Cabela’s now through June 10, 2020. You can save on GPS units, binoculars, packs, hiking boots, Knives/multi-tools, fishing gear, and yes firearms too. Check out the full selection of merchandise on Cabela’s Summer Sale Page. You’ll see a dozen featured selections, but scroll down and you can search for sale items by category.
Many of our readers have been curious about Hornady’s A-Tip bullets, but don’t want to spend $75-$85 to try out a full box. In addition, many of the more popular calibers and bullet weights are sold out. Now, thanks to Midsouth Shooters, you can try an A-Tip Sample Pack to see if A-Tips work in your barrel. Choose from four options: 110gr 6mm; 135gr 6.5mm; 153gr 6.5mm; and 250gr .308 caliber. All Sample Packs contain 10 bullets, and cost $9.99 at Midsouth.
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While Varget and Reloder 15 remain in short supply, you can often find IMR 4320 powder back in the shelves of local gun stores. IMR describes IMR 4320 as follows: “Short granulation, easy metering, and perfect for the 223 Remington, 22-250 Remington, 250 Savage and other medium burn rate cartridges.” This older-generation powder isconsiderably more temp sensitive than the Hodgdon Extreme propellants, but in the right application, it looks to be a viable alternative for folks who can’t source Varget, Reloder 15, and even H4895.
IMR 4320 Shoots Well in the .308 Winchester
A while back, GS Arizona wrote an excellent Riflemans Journal article, IMR 4320 — the Forgotten Powder. GS developed IMR 4320 loads for his .308 Win Palma rifle and competed with IMR 4320-powered ammo at long range matches. He concluded that: “[IMR 4320] appears to be a very useful alternative to some of the harder-to-get powders. The load is working extremely well at 1000 yards. In the [2009] Arizona Palma State Championship, several high-placing competitors were using the 4320 load. We got sub X-Ring elevation at 1000 yards from several rifles, and that’s all I’m looking for in a Palma load.”
IMR 4320 Works for Dasher Shooter
Forum member FalconPilot shoots a 6mm Dasher with Berger 105gr Hybrids. Looking for an alternative to Varget, he decided to give IMR 4320 a try. The results were good. FalconPilot reports: “I’ve been looking for other options (besides Reloder 15, which I love, but it’s really dirty). While at a gun shop in Ohio, I ran across 8 pounds of IMR 4320. I had never even heard of it, much less tried it. Getting ready for upcoming mid-range shoots, I loaded five rounds with IMR 4320 to the exact same specs as my winning Varget loads for the 6mm Dasher. This recipe was 32.7 grains of powder, Wolf SMR primer, Berger Hybrid 105 jumped fifty thousandths.” Falcon pilot tested his IMR 4320 load at 600 yards:
As you can see from the photo at the top of this article, FalconPilot had good results — a 1.5″ group at 600 yards. He reports: “This group was shoot during the middle of the day, mirage bad, scope set to 25X. It looks like IMR 4320 is a [very close] replacement for Varget… with a tad bit slower burn rate.” FalconPilot tell us the accuracy with IMR 4320 rivals the best he has gotten with Varget: “This gun has always shot under 2 inches [for 5 shots] at 600 yards, and most of time shoots 1.5 to 1.7 inches.”
For comparison purposes, here are Heat of Explosion and Burn Rate values from QuickLOAD for IMR 4320, and for the popular Reloder 15 and Varget powders. You can see that these powders have similar characteristics “by the numbers”:
Manufacturer
Powder Brand
Heat of Explosion
Burning Rate Factor
IMR
4320
3890
0.5920
Alliant
Reloder 15
3990
0.5200
Hodgdon (ADI)
Varget
4050
0.6150
WARNING — When changing from one powder to another, always start with manufacturer’s stated load data. Start low and work up incrementally. Never assume that loads will be equivalent from one powder to another, even powders with similar burn rates.
What Other Forum Members Say:
I was using IMR 4320 in the mid 70s in my .222 Rem. Darned great powder and I never had a load that was not accurate from the .222 to .30-06 with that powder. — 5Spd
A fine powder overshadowed by the nouveau wave of “gotta have the newest — make me a better shot” powders. Try 4320 in a 22-250 — what a well-kept secret! IMR 4320 meters very well and is a flexible alternative to many of the hard-to-find powders so much in demand. — AreaOne
IMR 4320 was my “go to” powder in my .223 for many many years. This powder and Winchester 55gr soft point bulk bullets (the cheapest bullet I could buy at the time) accounted for thousands of prairie dogs, coyotes, and anything else that needed shooting. I still use IMR 4320 in some .223 loads and am very happy with it still. — pdog2062
I’ve been using it in a .308 Win for several years. I think it is very sensitive to temperature and always waited till the last minute to load my ammo with a close eye on the weekend forecast at the range. IMR 4320 Works pretty good for 155gr Palma and 168gr Hybrid [bullets] in my .308. — JayC
IMR 8208 XBR is also good — if you can find it
Another good substitute for Varget powder in a .223 Rem or .308 Winchester is IMR 8208 XBR. In our own .308 Win tests, this generated slightly more velocity than Varget, with good ES/SD. However, this very good IMR 8208 XBR powder is out-of-stock at many vendors.
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Many of Hodgdon’s most popular powders, such as Varget and H4350, have become very hard to find. Shipments sell out as soon as they reach retailers’ shelves. We know our readers and Forum members are concerned about these supply shortages. Why are these powders in such short supply, and what is the prospect for more Varget, H4350, and other Hodgdon powders in the months ahead?
Hodgdon answered these (and other) questions recently in a Q&A post on the Hodgdon Facebook Page. Here are highlights of those Questions and Answers.
HODGDON POWDER UPDATE Frequently Asked Questions
Here are answers to your questions straight from Hodgdon, 1/31/2020:
Q: Why can’t I find Hodgdon powders like H4350, Varget, Retumbo, and H1000?
As you have seen, Hodgdon powders, especially rifle powders for long-range and precision shooting, can be difficult to find. Dealer shelves that were formerly filled with cans of powder now have empty spots. [Hodgdon added: “Dealer shelves are empty because powder is purchased as soon as it arrives at the dealers’ stores.”]
Q: Is Hodgdon still making powder?
A: Yes, we continue shipping powder as quickly as possible. In fact, we will ship more powder in 2020 than last year. The real problem behind empty dealer shelves is complicated, but is related to shifting supply and demand challenges. As supply decreased in 2019, demand only increased. No one wants to ship more powder than Hodgdon.
Q: What is causing the supply challenges?
A: Quite simply, our manufacturing facilities have not kept up with our orders. Additionally, military contracts began specifying Hodgdon powders in the last few years for military ammunition, impacting our supply. With expanded government regulation, shipping explosive and energetic materials has become more challenging, which also impacts available supply. Lastly, rapidly changing consumer preferences for different powder types has impacted both demand and supply. We worked with all Hodgdon providers to resolve open issues and expect powder supply to improve in 2020 as a result.
Varget, H4350, H4831SC, and other ‘Extreme Series’ powders are in very high demand.
Q: Is the shortage of reloading powder being caused by Hodgdon shipping their powder to the ammunition manufacturing companies?
A: While Hodgdon does sell powder to ammunition manufacturing companies, more than 80% of our powder is sold to our core market – handloaders just like you. Hodgdon has always been committed to the individual handloader.
Q: When will I start to see more powder on dealer shelves?
A: While Hodgdon will continue to ship powder as rapidly as possible, we have a significant backlog in demand. Some powders will be in stock more quickly, but we believe it will take much of 2020 to improve availability for all powders. [Editor: In a separate post, Hodgdon stated “We will be sending out large amounts of H4350 starting mid-March.”]
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When we first ran this story a while back, it spurred a hot debate, with strong opinions on both sides of the issue. Some guys argued vehemently that volumetric powder dispensing was best — citing the experience of short-range benchresters, most of whom still throw their charges. Others say weighing your charges is best, so long as you have a very precise, and very repeatable scale. Many of the top F-Class and 1000-yard shooters now weigh their charges to the kernel.
Most competitive long-range shooters weigh powder charges for their handloads. Some even use ultra-precise magnetic force restoration scales to load to single-kernel tolerances. But is weight-based measuring always the best way to fill a case with powder? Another option is volumetric charging. This method fills a precisely-sized cavity with powder and then dumps the charge into the case. A Harrell’s rotary powder measure works this way, as does the sliding powder filler on a Dillon progressive press.
For long-range applications, most people believe that precise weighing of powder charges is the best way to achieve optimal accuracy and low ES/SD. However, those short-range Benchrest guys do pretty darn well with their thrown charges, at least at 100 and 200 yards.
Our friend Dennis Santiago recently observed something that made him scratch his head and wonder about weighing charges. His AR-15 match rifle shot better with volumetric (cavity-measured) charges than with weighed charges dispensed by an RCBS ChargeMaster. Here’s what he reports:
Cavity vs. Dribble (Dennis Santiago Report) I had the chance to compare nominally identical ammunition loaded two ways. These were all .223 Remington match loads using 77gr Sierra Match Kings over 23.4 grains of Hodgdon Varget. Same gun. However I loaded some ammo with charges dispensed with a Lee cavity-style powder measure while other rounds were loaded with powder weighed/dispensed by an RCBS ChargeMaster. The cavity-drop ammo (with powder dropped from the Lee unit) was consistently better than the weighed-charge ammo. I have no idea why…
So, ladies and gentlemen — what do you think? Why did Mr. Santiago’s volumetrically-charged ammo shoot better than ammo filled with weighed charges? What’s your theory? Gary Eliseo suspects that Dennis’s Chargemaster might have been drifting. What do you think? Post your theories in the comments area below.
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Forum members are lamenting that they can’t find Hodgdon H4350 at local gunstores or through major online Vendors. There ARE a few shops that do have H4350 (and Varget) on the shelves. But the nearest H4350 may be in another state, far away. Therefore, you may want to consider using Alliant Reloder 16 (RL16). We highly recommend Reloder 16 for shooters who can’t find H4350. RL16 has a very similar burn rate, excellent accuracy, and is VERY temp stable. Some ace F-Class shooters (among Top 10 at Nationals) tell us that, with hot ambient temps (80-100+° F), RL16 is even more temp stable than H4350.
Powder Availability at Online Vendors — H4350, Reloder 16, Varget
*This is available in-store only at a few locations. You need to search store locations near you for availability. For example, H4350 8-pounders are available in a couple locations including Show Low, AZ and Midvale, UT. Varget 8-pounders are available in AZ, NM, and WY and a couple other states.
Do You Like H4350? Then You Should Try Reloder 16 — It Is Accurate and Temp Stable
Alliant Reloder 16 is used now by many top shooters for cartridges that work well with Hodgdon H4350. In fact, we’d say that Reloder 16 is the best substitute for H4350 on the market. Alliant’s RL 16 is very temp stable, offers good velocity, and the accuracy is top tier. Some guys report slightly better accuracy than H4350 in the .284 Win, .260 Rem, 6.5 Creedmoor, 6mm Creedmoor, and 6XC cartridges. If you currently use H4350, you should definitely give Alliant Reloder 16 a try. The powder also boasts excellent lot-to-lot consistency and contains a proprietary de-coppering additive.
This is NOT just a slower version of Alliant’s double-based Reloder 15 (which words great in the 6mmBR and Dasher cartridges). Reloder 16 is a completely new formulation, produced in Sweden by Bofors for Alliant. Reloder 16 utilizes TZ technology, which manipulates the response of the propellant and resists the natural tendency to generate more pressure at higher temperatures and less pressure at lower temperatures. As a result, Alliant’s Reloder 16 offers truly outstanding temperature stability.
With the 6mm Dasher cartridge becoming popular with PRS/NRL competitors as well as the benchrest crowd, we thought it was time to re-visit a special rifle chambered for the 6mm Dasher wildcat. This gun has a great story behind it. Forum member Bob A. (aka “Killshot”) used his “Forum Classifieds Special” to beat all comers in the F-Class Division in the American-Canadian Match and the Long Range Regional Match in 2013 in Sacramento, CA.
Bob’s 6mm Dasher sports a blue-printed Rem 700 action. Who says you need a high-dollar custom action to run with the big dogs? In fact, this same gun, built with components sourced from AccurateShooter Forum Classified Ads, set a Sacramento F-Class range record of 200-17X a few years back. In this story, Bob talks about the build, and he explains his methods for loading ultra-accurate Dasher ammo.
Bob’s Budget-Build Dasher F-Classer
I wanted to build a proper rifle for F-Open but needed to keep it simple and, well, cheap. I found a solid “base” to build on in the form of a Dave Bruno-built, “pre-owned” 6-6.5×47 Lapua that I located in the AccurateShooter Forum classifieds in late 2011. The base action was a trued and blue-printed Remington 700 receiver circa 1971 with a spiral-fluted bolt. It was in a Shehane ST1000 stock painted sky blue and had a Jewell 1.5-oz BR trigger. I sent the bolt to Greg Tannel (Gretanrifles.com) to have the firing pin hole bushed and sleeved, the ejector removed and the hole filled and the face trued. I upgraded to Tannel’s Light Steel firing pin assembly while it was out.
Having the working bits completed, I needed a barrel. So I went to the AccurateShooter classifieds again and found a 1:8″-twist, 30″ x 1.25″ (diam.) Bartlein with a 0.236″-land bore. I called Dave Kiff and explained my pursuit and he recommended his PT&G “world record” 6 Dasher reamer (.2704″ no-turn neck and .104″ freebore). A month or so later the reamer and gauges arrived.
I had the barrel chambered by Marc Soulie of Spartan Precision Rifles (510-755-5293, Concord, CA). Marc is a great builder and I’m pleased to call him a friend.
The rifle got its good looks from a Pennsylvania artist named Kenny Prahl. His Prahl Designs shop (724-478-2538) added the white ghost-flames over the existing sky blue metallic paint.
Looks Great, Shoots Better
Fire-forming showed great promise — ten-shot groups of half an inch at 200 yards were typical. I lost only one case to a split neck and the “blow lengths” are good and consistent. This was followed up with load development which saw 100-yard, five-shot groups in the .1s and .2s as the rifle showed its preference for Reloder 15 over Varget powder, and for CCI 450s over all other primers. The bullet of choice was the ever-popular Berger 105gr Hybrid Target.
In February 2012 I began shooting the Dasher in monthly club matches at the Sacramento Valley Shooting Center, the home range of a number of excellent F-Class, Benchrest and High Power shooters. Using a Farley Coaxial rest up front (also picked up from a WTB ad on AccurateShooter’s Forum) and an Edgewood bag in the back, I gradually improved my gun-handling to the point where I could shoot a respectable score. This was very different from the bipod shooting I’d done in the past in F/TR.
Dasher Loading Tips
My chamber is set up for blue box Lapua 6mmBR brass. My case preparation is straight-forward. I fire-form with virgin cases right out of the box. I don’t size them but I will give the primer holes a good look and clean up the flash hole with a .058″ bit in a pin vise. To fire-form, I seat a Berger 108gr BT .030″ into the lands over a standard 6mmBR load of Varget.
For match loads, I use Alliant Reloder 15. While Varget is less sensitive to temp changes, RL15 has given me lower extreme spreads and better long range control. [Bob acknowledges that every barrel is unique, so a different powder, such as H4895 might work better for you.]
I clean my fired cases with stainless steel media in a Thumler’s rotary tumbler after every firing. I anneal after every other firing using a Bench-Source machine which is very well made and easy to operate. I use a Whidden full length bushing die with Redding bushings for sizing.
After sizing, I chamfer the inside of the neck with the K&M tool which has a pilot rod centered in the flash hole. Then I’ll give the neck and mouth a “once over” with some 0000 steel wool. I finish loading off with a Redding Competition Seating Die with the micrometer top.
I use a carbide ball on the expander rod of the full length sizing die. I use a .266″ TiN-coated bushing and the ball just kisses the inside walls of the sized neck. I get very consistent neck tension this way and have had no issue with split necks.
Seating Depth Considerations
With fire-formed brass, the junction of the bullet’s bearing surface and boat-tail is above the neck/shoulder junction of the case, so I have no issues with donuts. You can see how a loaded round looks in the photo at left. For occasional trimming, I use a very nice little Possum Hollow trimmer that indexes on the case shoulder.
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The New 6GT Cartridge for Precision Rifle Competition
Report by Vu Pham
Earlier this year I was ready to build a 6 Dasher when I saw a lot of buzz on the interwebs about a new caliber George Gardner (Owner of GA Precision) and Tom Jacobs (Owner of Vapor Trail Bullets) designed, the 6GT. After some research and talking to George, I ditched the 6mm Dasher build and had GA Precision build me a 6GT on a GAP Templar action I already had in the safe. The reasons to try the 6GT in a new PRS-style rig were as follows:
1. Push a 110-115 grain class bullet at 2880-2930 FPS safely in the Sacramento heat.
2. Achieve a load that is reliable and predictable. The caliber must be easy-to-tune and predictable from barrel to barrel. I don’t want to spend weeks developing a new load each time I spin on a fresh barrel.
3. Be able to run the same mag in all my guns without having to tweak or use mag kits. The round must feed from AICS and AW magazines without major tweaking or hiccups.
4. Get good barrel life. The barrel needs to go 2200-2500 rounds with match-grade reliability and accuracy.
5. Have a competitive cartridge with the least possible recoil without sacrificing too much performance down range, compared to bigger options like the 6mm Creedmoor.
6GT feeding from un-modified magazines has been flawless in all the rifles we tested. The 6GT feeds so well, I sometimes have to do a press check to ensure there is a round in the chamber.
On paper the 6GT seemed like the perfect cartridge for PRS- and NRL-style competition. It has the low recoil of a 6 Dasher, with good feeding and mag compatibility. With the 6GT, a competitor can push 105gr bullets at 3000+ FPS or run heavier bullets at 2800-2900+ FPS.
Knowing that I would initially have to make my own 6GT brass and do quite a bit of load development, I enlisted the help of Dan Bertocchini with CS Tactical. Dan has a lot more experience with wildcats and is the man when it comes to this type of data gathering. He has been running a 6 Dasher for a few years so I was curious how he would compare the 6GT to his 6 Dasher.
Quick Summary: “I am really digging the 6GT and the capabilities it offers. It can launch 103gr Vapor Trails at 3000+ FPS or lob heavy 115gr DTACs in the low-to-mid 2900s comfortably. I think we will see this cartridge go mainstream in PRS/NRL-style competition in 2020.” — Vu Pham
The new 6GT Cartridge Was Tested in Three (3) Tactical Rifles:
Rifle 1: Vu’s 6GT 1.0
Builder: GA Precision
Action: Left Hand GAP Templar (large firing pin)
Barrel: Bartlein 7.7 Twist finished at 26″ with a 419 Hellfire Brake
Stock: KMW Sentinel
Optic: Vortex Razor Gen II 4.5-27x56mm EBR-7C MRAD
Bi-Pod: Harris
Trigger: Timney Calvin Elite
Magazines: AICS and AW
Support Bag: Wiebad Fortune Cookie
Rifle 2: Vu’s 6GT 2.0
Builder: Rubicon Precision
Action: Impact Precision 737
Barrel: Bartlein 7.0 Twist finished at 27″ with a 419 Hellfire Brake
Stock: XLR Industries Envy Chassis
Optic: Vortex Razor Gen II 4.5-27x56mm EBR-7C MRAD
Bi-Pod: Harris with Henderson Arca adapter
Trigger: Trigger Tech Diamond
Magazines: AICS and AW
Support Bag: Wiebad Fortune Cookie
Rifle 3: Dan’s 6GT
Builder: CS Tactical
Chambered by: Rubicon Precision
Action: Lone Peak Arms Fusion
Barrel: Proof 7.0 Twist finished at 28″ with a Muzzle Brake and More Brake
Stock: XLR Industries Envy Chassis
Optic: Minox ZP5 5-25x56mm MR4
Bi-Pod: Arca Cyke Pod (PRS)
Trigger: Trigger Tech Diamond
Magazines: MDT
Support Bag: Armageddon Gear OG Game Changer, Waxed Canvas
Alpha Munitions Pre-Production 6GT Brass George Gardner was kind enough to send us 50 pieces of Pre-Production Alpha 6GT brass for preliminary testing. Like the cases I formed from 6.5×47 Lapua brass, the Alpha 6GT brass will use a small rifle primer. Price from Alpha Munitions should be $1.15 per case, which is on par with Alphan’s other product line.
The first 7000 pieces of Alpha 6GT brass sold before I could even get my hands on any! The bigger batch of production brass is due later this year. To pre-order the brass, CLICK HERE.
The major difference between 6.5×47 Lapua-formed brass and Alpha 6GT brass is the case capacity. Alpha 6GT brass has 1.5 to 1.7 grains more case capacity. When a piece of 6.5×47 Lapua brass is formed into a 6GT, the walls of the case now become the shoulder and part of the neck. In a normal piece of brass, the shoulder and neck are typically thinner because of the thickness of the brass tapering from the body to neck.
While the cartridge design was optimized for Hodgdon Varget, the extra case capacity of the Alpha 6GT brass opens the door to Hodgdon H4350 (my favorite powder) and Alliant Reloder 16.
Test Results with Alpha Munitions 6GT Brass
Initial test results were as expected from a premium brass-maker. Dan and I both got excellent Standard Deviations and Extreme Spreads over my MagnetoSpeed V3 and his LabRadar. This string below was with 112gr Barnes Match Burners and 33.8 grains of Varget. Can’t complain about a 3 FPS Extreme Spread!
Yes, H4350 Works with the Alpha Munitions Brass
Personally, I prefer running Alpha 6GT brass with H4350 rather than Varget pushing a heavier bullet. H4350 burns slower and cleaner which should equate to better barrel life. The Lapua-formed 6GT cases just do not have the capacity to reach the cartridge’s full capability with the slower burning powders.
Is the 6GT cartridge accurate? Definitely. Here is a 5-shot group at 600 yards shot by Dan. This was Alpha 6GT brass, with Hodgdon H4350 pushing Barnes 112gr Match Burner bullets.
And here is a 4-shot, 600-yard group with reformed 6.5×47 Lapua brass, using Varget powder under a Barnes 112gr Match Burner.
6GT Stress Test — Don’t Try this at Home!
Dan and I also did a “destruction test” to see how the Alpha 6GT brass would hold up when competitors push the cartridge to its limits. Please note that this is PRE-PRODUCTION brass and Dan and I probably exceeded max load for the majority of the duration of this test. Using Varget powder, we pushed 115gr DTACs at 2950+ FPS on a pretty hot day. We ran the charge weight up until the bolt was hard to lift.
Using this very hot charge, we were able to get 14 firings before the primer pocket failed. That is pretty solid considering that this brass was a pre-production sample that Alpha said did not meet its primer pocket design requirements. With these results, I think a shooter pushing 110-115 grain class bullets in the low 2900s will get 16 to 20 firings from a piece of brass.
Is the GT here to stay?
All signs are pointing to “Yes”. Dies are readily available from Hornady, RCBS, and Redding. Chamber reamers are being produced by PT&G and JGS that can be purchased through GA Precision.
Alpha Munitions is hard at work getting quality brass to the shooters. Quite a few people have already chambered up 6GT barrels before they even have brass in hand. I think we will see this cartridge go mainstream in PRS/NRL-style competition in 2020. With Alpha Munitions production brass almost ready to hit the shelves, I think we will see a lot more data come in from the field by the end of this year.
The Verdict — The 6GT Is Looking Great So Far
I am really digging the 6GT and the capabilities it offers. It can launch 103gr Vapor Trails at 3000+ FPS or lob heavy 115gr DTACs in the low to mid 2900s comfortably. George Gardner has texted me some pictures of very impressive groups pushing an 115gr DTAC at 3000 FPS with Alliant Reloder 16 (a very temp-stable powder with a burn rate close to H4350). That being said, if a guy wanted to push that type of speed and bullet weight, the 6mm Creedmoor is a better solution in my opinion. So far my “go to” 6GT load is a 112gr Barnes Match Burner at 2900 FPS. My other favorite load is a Hornady 108gr ELDM at 2970 FPS.
I think the down-range performance of the 6GT over a 6mmBR and the 6BR variants will be valuable on those days where shooting conditions are not as perfect. Recoil is about the same as the 6BR variants (6BRA, 6 Dasher etc.), but noticeably less than a 6mm Creedmoor. The extra energy down range will make a spotter’s job a bit easier when targets extend beyond 800 yards.
Forming GT Brass from Lapua 6.5×47
Before the new Alpha Munitions brass was available, I tested the cartridge using 6GT made from parent Lapua 6.5×47 Lapua brass necked-down and reformed. George Gardner walked me through the process of forming 6GT brass out of Lapua 6.5x47L. The process is time-consuming and is a huge PITA even with the correct tools. More detailed instructions can be found on my 6GT thread on the AccurateShooter Forum. READ Forum Thread HERE.
Here is a photo of what the brass looks like going through the forming/trimming process.
Left to right: 6.5×47 Lapua brass, sized with the 6GT bushing die with a .266 bushing, chopped/trimmed and turned, and fired-formed.
The formed-from-Lapua 6GT brass performed well and is a good option if one has the time and desire, but I’ll be moving over to factory Alpha Munitions brass once it is readily available.
6GT Tested at 1000 Yards
After seeing what Tom Jacobs is doing with his benchrest gun running Alpha Munitions brass, there is no doubt the 6GT is plenty capable out to 1000 yards and beyond. I have a feeling the Benchrest and F-Open guys are going to dig this new 6mm cartridge as well, at least for 600 yards. Note, in this photo it appears Shot #5 is under a paster, but that might just be a Ballistic-X software input error, meaning that this is actually a 4-shot group. Either way it is still impressive.
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Well folks, it’s July 6th already — the means we’re moving into “peak heat” summer conditions. It’s vitally important to keep your ammo at “normal” temps during the hot summer months. Even if you use “temp-insensitive” powders, studies suggest that pressures can still rise dramatically when the entire cartridge gets hot, possibly because of primer heating. It’s smart to keep your loaded ammo in an insulated storage unit, possibly with a Blue Ice Cool Pak if you expect it to get quite hot. Don’t leave your ammo in the car or truck — temps can exceed 140° in a vehicle parked in the sun.
To learn more about how ambient temperature (and primer choice) affect pressures (and hence velocities) you should read the article Pressure Factors: How Temperature, Powder, and Primer Affect Pressure by Denton Bramwell. In that article, the author uses a pressure trace instrument to analyze how temperature affects ammo performance. Bramwell’s tests yielded some fascinating results.
For example, barrel temperature was a key factor: “Both barrel temperature and powder temperature are important variables, and they are not the same variable. If you fail to take barrel temperature into account while doing pressure testing, your test results will be very significantly affected. The effect of barrel temperature is around 204 PSI per F° for the Varget load. If you’re not controlling barrel temperature, you about as well might not bother controlling powder temperature, either. In the cases investigated, barrel temperature is a much stronger variable than powder temperature.”
Powder Heat Sensitivity Comparison Test
Our friend Cal Zant of the Precision Rifle Blog recently published a fascinating comparison test of four powders: Hodgdon H4350, Hodgdon Varget, IMR 4451, and IMR 4166. The first two are Hodgdon Extreme powders, while the latter two are part of IMR’s Enduron line of propellants.
The testers measured the velocity of the powders over a wide temperature range, from 25° F to 140° F. Hodgdon H4350 proved to be the most temp stable of the four powders tested.
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To learn more about how ambient temperature (and primer choice) affect pressures (and hence velocities) you should read the article 
While Varget and Reloder 15 remain in short supply, you can often find IMR 4320 powder back in the shelves of local gun stores. IMR describes IMR 4320 as follows: “Short granulation, easy metering, and perfect for the 223 Remington, 22-250 Remington, 250 Savage and other medium burn rate cartridges.” This older-generation powder is considerably more temp sensitive than the Hodgdon Extreme propellants, but in the right application, it looks to be a viable alternative for folks who can’t source Varget, Reloder 15, and even H4895.
Most competitive long-range shooters weigh powder charges for their handloads. Some even use ultra-precise magnetic force restoration scales to load to single-kernel tolerances. But is weight-based measuring always the best way to fill a case with powder? Another option is volumetric charging. This method fills a precisely-sized cavity with powder and then dumps the charge into the case. A 
Dasher Loading Tips
I use a carbide ball on the expander rod of the full length sizing die. I use a .266″ TiN-coated bushing and the ball just kisses the inside walls of the sized neck. I get very consistent neck tension this way and have had no issue with split necks.
George Gardner was kind enough to send us 50 pieces of Pre-Production Alpha 6GT brass for preliminary testing. Like the cases I formed from 6.5×47 Lapua brass, the Alpha 6GT brass will use a small rifle primer. Price from 
