Our Sunday GunDay showcase rifle belongs to Shane Sivertsen (aka SoDakDasher in our Forum). This eye-catching tactical rig was smithed by Travis Stevens at TS Customs in Miller, South Dakota. Shane tells us that Travis is a “top-notch builder who builds tack-driving rifles that are still extremely shooter-friendly. Plus he is one of the friendliest guys you’ll meet.”

This rifle features a Lone Peak Fuzion Action with Trigger Tech Diamond trigger (flat shoe). Up front is a Benchmark 26″ MTU barrel chambered in 6mm BRA (a 40-degree 6mmBR Improved “BR Ackley”). It’s all nestled into a McMillan A5 stock with adjustable cheekpiece. Getting him on target is a Vortex Razor 4.5-27x56mm optic in Hawkins rings with a Vortex throw lever on the power ring for quick magnification changes. The Atlas PRS Bipod rides on an Area 419 ARCA rail up front. The barrel is finished off with a Piercision 5-Port Self-Timing Muscle Brake.

Custom Camo-Pattern Paint Job
All work on this rig was performed at TS Customs, including Cerakoting the action. The pattern on the McMillan A5 stock is NOT a hydro-dip! That is a custom Kryptek camo paint-job done in-house by a TS Customs employee. Shane liked the Kryptek pattern from day one: “It’s always a good thing to do something a little different to your equipment to stand apart from the rest of the pack.” Shane says the paint pattern is the first thing everyone notices about the rifle.

6mm BRA Chambering
Shane spent quite some time trying to decide which 6mm cartridge to choose. After much deliberation with Travis, he chose the 6mm BRA (aka “6BRA” or “6 BRA”), mainly due to the reputation this little cartridge has earned for accuracy and ease of tuning. This rifle is Shane’s second TS Customs-crafted rifle: “the [other] is basically the same action/barrel combo but set in an MPA chassis and chambered in 6mm Dasher.”

Excellent Accuracy with Varget and Berger 105gr Hybrids
Shane’s 6mm BRA is showing impressive accuracy: “Thanks to Mother Nature this spring (with cold, snowy weather), I have only been able to get 100 rounds fire-formed and the barrel broken-in. I started with 30.5 grains Varget in Lapua BR brass with CCI 450s and topped off with Berger 105gr Hybrids. Velocity averaged 2830 FPS with an SD of 4.7 from 10 rounds randomly picked from the lot.”

Shane knows there’s still more load development to do. But this rifle is grouping under one-half MOA and Shane says the gun can definitely out-shoot his abilities. He admits it’s still a work in progress but he is happy with the gun’s performance so far.

Shane praised his Piercision 5 port Muscle brake. Shane tells us: “While I am a suppressed shooter by preference, I wanted to give this brake a try. It works very well — the control and ability to stay on target for followups is remarkable. This brake works perfect on my 18-lb 6mm BRA and will be used indefinitely. Plus it will be a little payback to the other big-braked shooters on the line.”

While it’s still such a new toy, Shane doesn’t expect to make any modifications in the near future. However he says he might “upgrade to a Tangent Theta optic by the end of this season.”

Below is a comparison between the 6mm BRA and the 6mm Dasher. The Dasher has slightly more capacity, but a much shorter neck. There is some evidence that barrel throat erosion may be slower with the 6mm BRA, and the 6mm BRA is easier to fire-form.

Put the same load in a variety of barrels (with the same length and chamberings) and you’ll see a wide variance in muzzle velocity. In fact, it’s not unusual to see up to 100 fps difference from one barrel to the next. We demonstrated this with a comparison test of Lapua factory ammo.

Chron Testing Lapua Factory Ammo
At our Southern California test range some years ago, we chronographed Lapua 105gr 6mmBR factory ammo in three different 8-twist barrels of similar length. The results were fascinating. Lapua specs this ammo at 2790 fps, based on Lapua’s testing with its own 26″ test barrel. We observed a speed variance of 67 fps based on tests with three aftermarket barrels.

Barrel Velocity Variance
Brand ‘S’ and Brand ‘PN’ were pre-fit barrels shot on Savage actions. Brand ‘K’ was fitted to a custom action. All test barrels were throated for the 100-108 grain bullets, though there may have been some slight variances in barrel freebore. With a COAL of 2.330″, the rounds were “jumping” to the rifling in all barrels.

Among the four barrels, Brand ‘PN’ was the fastest at 2824 fps average — 67 fps faster than the slowest barrel. Roughly 10 fps can be attributed to the slightly longer length (27″ vs. 26″), but otherwise this particular barrel was simply faster than the rest. (Click Here for results of 6mmBR Barrel Length Velocity Test).

IMPORTANT: Results Are Barrel-Specific, Not Brand-Specific

These tests demonstrate that the exact same load can perform very differently in different barrels. We aren’t publishing the barrel-makers’ names, because it would be wrong to assume that ‘Brand X’ is always going to be faster than ‘Brand Y’ based on test results from a single barrel. In fact, velocities can vary up to 100 fps with two identical-spec barrels from the SAME manufacturer. That’s right, you can have two 8-twist, 26″ barrels, with the same land-groove configuration and contour, from the same manufacturer, and one can be much faster than another.

Don’t Demand More Than Your Barrel Can Deliver
We often hear guys lament, “I don’t get it… how can you guys get 2900 fps with your 6BRs and I can only get 2840?” The answer may simply be that the barrel is slower than average. If you have a slow barrel, you can try using more powder, but there is a good chance it may never run as fast as an inherently fast barrel. You shouldn’t knock yourself out (and over-stress your brass) trying to duplicate the velocities someone else may be getting. You need to work within the limits of your barrel.

Factory Ammo Provides a Benchmark
If you have a .223 Rem, 6mmBR, .243 Win, 6.5×47 Lapua, 6.5 Creedmoor, 6.5×55, .308 Win, .30-06 Springfield, or .338 LM Rifle, we recommend you buy a box of Lapua factory-loaded ammo. This stuff will shoot great (typically around half-MOA), and it can give you a baseline to determine how your barrel stacks up speedwise. [Editor’s NOTE: The original test was conducted in 2008. The velocity of current-production Lapua factory ammo might be higher or lower, so your results may vary.]

When you complete a new 6mmBR rifle, it’s definitely smart to get a box of the factory ammo and chronograph it. That will immediately give you a good idea whether you have a slow, average, or fast barrel. Then you can set your velocity goals accordingly. For example, if the factory 6BR ammo runs about 2780-2790 fps in your gun, it has an average barrel. If it runs 2820+ in a 26″ barrel (or 2835 fps in a 28″), you’ve got a fast tube.

Put the same load in a variety of barrels (with the same length and chamberings) and you’ll see a wide variance in muzzle velocity. In fact, it’s not unusual to see up to 100 fps difference from one barrel to the next. We demonstrated this with a comparison test of Lapua factory ammo.

Chron Testing Lapua Factory Ammo
At our Southern California test range some years ago, we chronographed Lapua 105gr 6mmBR factory ammo in three different 8-twist barrels of similar length. The results were fascinating. Lapua specs this ammo at 2790 fps, based on Lapua’s testing with its own 26″ test barrel. We observed a speed variance of 67 fps based on tests with three aftermarket barrels.

Barrel Velocity Variance
Brand ‘S’ and Brand ‘PN’ were pre-fit barrels shot on Savage actions. Brand ‘K’ was fitted to a custom action. All test barrels were throated for the 100-108 grain bullets, though there may have been some slight variances in barrel freebore. With a COAL of 2.330″, the rounds were “jumping” to the rifling in all barrels.

Among the four barrels, Brand ‘PN’ was the fastest at 2824 fps average — 67 fps faster than the slowest barrel. Roughly 10 fps can be attributed to the slightly longer length (27″ vs. 26″), but otherwise this particular barrel was simply faster than the rest. (Click Here for results of 6mmBR Barrel Length Velocity Test).

IMPORTANT: Results Are Barrel-Specific, Not Brand-Specific

These tests demonstrate that the exact same load can perform very differently in different barrels. We aren’t publishing the barrel-makers’ names, because it would be wrong to assume that ‘Brand X’ is always going to be faster than ‘Brand Y’ based on test results from a single barrel. In fact, velocities can vary up to 100 fps with two identical-spec barrels from the SAME manufacturer. That’s right, you can have two 8-twist, 26″ barrels, with the same land-groove configuration and contour, from the same manufacturer, and one can be much faster than another.

Don’t Demand More Than Your Barrel Can Deliver
We often hear guys lament, “I don’t get it… how can you guys get 2900 fps with your 6BRs and I can only get 2840?” The answer may simply be that the barrel is slower than average. If you have a slow barrel, you can try using more powder, but there is a good chance it may never run as fast as an inherently fast barrel. You shouldn’t knock yourself out (and over-stress your brass) trying to duplicate the velocities someone else may be getting. You need to work within the limits of your barrel.

Factory Ammo Provides a Benchmark
If you have a .223 Rem, 6mmBR, .243 Win, 6.5×47 Lapua, 6.5 Creedmoor, 6.5×55, .308 Win, .30-06 Springfield, or .338 LM Rifle, we recommend you buy a box of Lapua factory-loaded ammo. This stuff will shoot great (typically around half-MOA), and it can give you a baseline to determine how your barrel stacks up speedwise. [Editor’s NOTE: The original test was conducted in 2008. The velocity of current-production Lapua factory ammo might be higher or lower, so your results may vary.]

When you complete a new 6mmBR rifle, it’s definitely smart to get a box of Lapua factory ammo and chronograph it. That will immediately give you a good idea whether you have a slow, average, or fast barrel. Then you can set your velocity goals accordingly. For example, if the factory 105gr 6BR ammo runs about 2780-2790 fps in your gun, it has an average barrel. If it runs 2820+ in a 26″ barrel (or 2835 fps in a 28″), you’ve got a fast tube.

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.

For today’s Sunday GunDay story, we feature highlights from two in-depth reports on rifles built around the relatively new 6GT cartridge (also known as the “6mm GT”). Developed by George Gardner (G.A. Precision) and Tom Jacobs (Vapor Trail), the 6GT was designed to feed well from magazines, be more efficient than the 6mm Creedmoor, and offer outstanding accuracy. It is just enough bigger than the 6mmBR or 6 Dasher so it feeds better. But it retains many of the qualities of the 6mmBR (high efficiency and outstanding accuracy). Burning significantly less powder than the 6mm Creedmoor, the 6GT is a bit less expensive to shoot, and should, theoretically at least, deliver better barrel life.

“The [6GT] is a more predictable and barrel-friendly cartridge than the 6mm Creedmoor. It can utilize the accurate and forgiving powders of the 6BR, has fantastic accuracy, and due to its shoulder angle and case length, it doesn’t suffer from feeding issues.” — PewPewTactical.com

We should say that the 6 Dasher has been used very successfully in PRS/NRL competition, with some aftermarket magazine accessories. For this reason, if you already shoot a 6 Dasher, moving to a 6GT may not be worth the cost of new dies and new brass. A.J. Deysel, writing for LoadDevelopment.com, writes:

“The longer case of the 6mm GT means it feeds as reliably from a magazine as a 6mm Creedmoor, and offers slightly higher powder capacity and in turn velocities than the 6mmBR variants, whilst still being able to use the same accurate and forgiving propellants.

You will also find many competitive and average Joes shooting 6mmBR and 6mm Dashers with a Primal Rights or some other mag conversion kit, having very few if any mag-feed issues at all, so that pretty much also nullifies the need to move away from those [chamberings] if you already own one of those or the reloading equipment for it.” — LoadDevelopment.com

Part I: The 6GT Cartridge for Precision Rifle Competition

Report by Vu Pham
I was ready to build a 6 Dasher when I saw a lot of buzz… about a new caliber George Gardner (Owner of G.A. 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

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. Purchased direct from Alpha Munitions, 6GT brass is now $1.30 per case, which is comparable with Lapua 6mm Creedmoor brass, currently $120.99/100 at Grafs.com.

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.

PART II — 6GT Load Development with Multiple Powders

This text is taken from a full report by Mike McCasland on his 6GT (aka “6mm GT”) bolt action rifle. This rig was designed for general use, not just for PRS/NRL matches. In his 6GT rifle, Mike tested multiple powders including Varget, H4350, Reloder 16, Reloder 15, Shooters World Precision, and Vihtavuori N140. For more details, CLICK HERE for full report.

About the 6mm GT Cartridge

BRASS — The first thing you’ll find is cartridge brass choices for the 6 GT are rather limited currently. At present, the only commercial options are Hornady and Alpha Munitions. For the die-hard Lapua fans, you can technically make 6mm GT brass from 6.5×47 Lapua, however that process is very labor-intensive.

I have used both Hornady and Alpha brass in this rifle and haven’t noticed much difference between the two. I will say that my batch of Alpha brass was slightly softer than Alpha brass I’ve used in other calibers; you could feel a difference when neck turning cases. I’m unsure if that’s a batch issue, or something specific to their 6mm GT brass as a whole. As far as performance, there was little discernable difference. Oddly enough, the Hornady brass seemed to have slightly less case capacity than the Alpha; with most other cartridges it’s the other way around.

POWDERS — The 6mm GT was designed with Hodgdon Varget in mind, and that popular powder works exceedingly well in this platform. That said, the 6mm GT can work with a wide variety of powders, some yielding better performance than Varget.

I’ve tried a multitude of powders during my initial 6mm GT load development: Varget, Shooters World Precision, RL16, VV N140, H4350, and RL-15 to name a few. In my barrel, Hodgdon H4350 seems to deliver the best velocity/accuracy combination. SD and ES also seemed to be the lowest with H4350.

Load Development for the 6mm GT — Many Powders Tested

BULLETS — The most common 0.120″ freebore chamber allows for the majority of high-BC 6mm projectiles found in both F-Class and PRS. I had good luck with the pointed 107gr Sierra Match Kings (SMK), as well as the 110gr Hornady A-Tips in my rifle. For those looking to run the heavier 112-115 grain 6mm offerings, I believe GAP designed a 0.160″ freebore reamer that gets those bullets out of the neck/shoulder junction. Shown below is the 0.120″ freebore JGS reamer print:

SUMMARY — Good Cartridge with Much Potential
Generally speaking, I think the 6mm GT is a good little round. Some may not subscribe to this theory, but I believe some cartridges are inherently easier to tune than others. I’m not sure the 6mm GT is as easy-to-tune as a 6mmBR, 6 Dasher, or 6 BRA, but I don’t think it lags that far behind.

With relatively little trouble, I was able to find loads with both Varget and H4350 that would consistently shoot very well — 0.2 to 0.3 MOA. Moreover, I found the 6GT cartridge lives up to the velocity claims made by G.A. Precision. I was easily able to push the 110gr A-Tips to 2950 FPS, and the 107gr SMKs to low 3000 FPS range without any pressure signs, or unnecessary wear and tear on the brass.

As a fun test, I ran my 6mm GT rifle in a local 1000-yard F-Class match with the 110gr A-Tips, just to see just how well they would perform. Although wind conditions of the day and some E-Target issues prevented my 6mm GT rig from getting the better of the larger 7mm and .30-Cal rifles, the 6mm GT proved itself an accurate little round at distance. Here is a 1000-yard ShotMarker target:

After putting several hundred rounds through my 6mm GT rifle, I anticipate building another 6GT on a repeater action to give PRS a try. I think if you are looking for a dual-purpose rifle that can run tactical matches (with 100% feeding reliability), and can also be used for mid-range, F-Open Class competition, the 6mm GT would be a very good option.

About the author, Mike McCasland:
Mike McCasland is an avid shooter who competes regularly in F-Class matches. Based in Texas, Mike is the creator of the Texas Precision YouTube Channel. There you’ll find many videos covering reloading, gun projects, and marksmanship. Mike has done some notable product reviews including a comparison test of Micrometer Competition Seating Dies. To access Mike’s YouTube Channel, CLICK HERE.

Put the same load in a variety of barrels (with the same length and chamberings) and you’ll see a wide variance in muzzle velocity. In fact, it’s not unusual to see up to 100 fps difference from one barrel to the next. We demonstrated this with a comparison test of Lapua factory ammo.

Chron Testing Lapua Factory Ammo
At our Southern California test range some years ago, we chronographed Lapua 105gr 6mmBR factory ammo in three different 8-twist barrels of similar length. The results were fascinating. Lapua specs this ammo at 2790 fps, based on Lapua’s testing with its own 26″ test barrel. We observed a speed variance of 67 fps based on tests with three aftermarket barrels.

Barrel Velocity Variance
Brand ‘S’ and Brand ‘PN’ were pre-fit barrels shot on Savage actions. Brand ‘K’ was fitted to a custom action. All test barrels were throated for the 100-108 grain bullets, though there may have been some slight variances in barrel freebore. With a COAL of 2.330″, the rounds were “jumping” to the rifling in all barrels.

Among the four barrels, Brand ‘PN’ was the fastest at 2824 fps average — 67 fps faster than the slowest barrel. Roughly 10 fps can be attributed to the slightly longer length (27″ vs. 26″), but otherwise this particular barrel was simply faster than the rest. (Click Here for results of 6mmBR Barrel Length Velocity Test).

IMPORTANT: Results Are Barrel-Specific, Not Brand-Specific

These tests demonstrate that the exact same load can perform very differently in different barrels. We aren’t publishing the barrel-makers’ names, because it would be wrong to assume that ‘Brand X’ is always going to be faster than ‘Brand Y’ based on test results from a single barrel. In fact, velocities can vary up to 100 fps with two identical-spec barrels from the SAME manufacturer. That’s right, you can have two 8-twist, 26″ barrels, with the same land-groove configuration and contour, from the same manufacturer, and one can be much faster than another.

Don’t Demand More Than Your Barrel Can Deliver
We often hear guys lament, “I don’t get it… how can you guys get 2900 fps with your 6BRs and I can only get 2840?” The answer may simply be that the barrel is slower than average. If you have a slow barrel, you can try using more powder, but there is a good chance it may never run as fast as an inherently fast barrel. You shouldn’t knock yourself out (and over-stress your brass) trying to duplicate the velocities someone else may be getting. You need to work within the limits of your barrel.

Factory Ammo Provides a Benchmark
If you have a .223 Rem, 6mmBR, .243 Win, 6.5×47 Lapua, 6.5 Creedmoor, 6.5×55, .308 Win, .30-06 Springfield, or .338 LM Rifle, we recommend you buy a box of Lapua factory-loaded ammo. This stuff will shoot great (typically around half-MOA), and it can give you a baseline to determine how your barrel stacks up speedwise. [Editor’s NOTE: The original test was conducted in 2008. The velocity of current-production Lapua factory ammo might be higher or lower, so your results may vary.]

When you complete a new 6mmBR rifle, it’s definitely smart to get a box of the factory ammo and chronograph it. That will immediately give you a good idea whether you have a slow, average, or fast barrel. Then you can set your velocity goals accordingly. For example, if the factory 6BR ammo runs about 2780-2790 fps in your gun, it has an average barrel. If it runs 2820+ in a 26″ barrel (or 2835 fps in a 28″), you’ve got a fast tube.

Put the same load in a variety of barrels (with the same length and chamberings) and you’ll see a wide variance in muzzle velocity. In fact, it’s not unusual to see up to 100 fps difference from one barrel to the next. We demonstrated this with a comparison test of Lapua factory ammo.

Chron Testing Lapua Factory Ammo
At our Southern California test range some years ago, we chronographed Lapua 105gr 6mmBR factory ammo in three different 8-twist barrels of similar length. The results were fascinating. Lapua specs this ammo at 2790 fps, based on Lapua’s testing with its own 26″ test barrel. We observed a speed variance of 67 fps based on tests with three aftermarket barrels.

Barrel Velocity Variance
Brand ‘S’ and Brand ‘PN’ were pre-fit barrels shot on Savage actions. Brand ‘K’ was fitted to a custom action. All test barrels were throated for the 100-108 grain bullets, though there may have been some slight variances in barrel freebore. With a COAL of 2.330″, the rounds were “jumping” to the rifling in all barrels.

Among the four barrels, Brand ‘PN’ was the fastest at 2824 fps average — 67 fps faster than the slowest barrel. Roughly 10 fps can be attributed to the slightly longer length (27″ vs. 26″), but otherwise this particular barrel was simply faster than the rest. (Click Here for results of 6mmBR Barrel Length Velocity Test).

IMPORTANT: Results Are Barrel-Specific, Not Brand-Specific

These tests demonstrate that the exact same load can perform very differently in different barrels. We aren’t publishing the barrel-makers’ names, because it would be wrong to assume that ‘Brand X’ is always going to be faster than ‘Brand Y’ based on test results from a single barrel. In fact, velocities can vary up to 100 fps with two identical-spec barrels from the SAME manufacturer. That’s right, you can have two 8-twist, 26″ barrels, with the same land-groove configuration and contour, from the same manufacturer, and one can be much faster than another.

Don’t Demand More Than Your Barrel Can Deliver
We often hear guys lament, “I don’t get it… how can you guys get 2900 fps with your 6BRs and I can only get 2840?” The answer may simply be that the barrel is slower than average. If you have a slow barrel, you can try using more powder, but there is a good chance it may never run as fast as an inherently fast barrel. You shouldn’t knock yourself out (and over-stress your brass) trying to duplicate the velocities someone else may be getting. You need to work within the limits of your barrel.

Factory Ammo Provides a Benchmark
If you have a .223 Rem, 6mmBR, .243 Win, 6.5×47 Lapua, 6.5 Creedmoor, 6.5×55, .308 Win, 30-06, or .338 LM Rifle, we recommend you buy a box of Lapua factory-loaded ammo. This stuff will shoot great (typically around half-MOA), and it can give you a baseline to determine how your barrel stacks up speedwise. [Editor’s NOTE: The original test was conducted in 2008. The velocity of current-production Lapua factory ammo might be higher or lower, so your results may vary.]

When you complete a new 6mmBR rifle, it’s definitely smart to get a box of the factory ammo and chronograph it. That will immediately give you a good idea whether you have a slow, average, or fast barrel. Then you can set your velocity goals accordingly. For example, if the factory 6BR ammo runs about 2780-2790 fps in your gun, it has an average barrel. If it runs 2820+ in a 26″ barrel (or 2835 fps in a 28″), you’ve got a fast tube.

Compared to a .223, the 6BR offers a better selection of high-BC projectiles and small-maker match projectiles (such as Bart Sauter’s “Hammer” and the Vapor Trail line). The 6BR will also deliver considerably more power on the target. Compared to the .308 shooting 168gr MatchKings, a 6BR shooting 105-107gr bullets offers better ballistics all the way out to 1000 yards. (The story changes with .308s with very long barrels pushing the 180-210 grain projectiles). Plus, for most people, the 6BR is just easier to shoot than a .308. Recoil is less than half of the .308 Win cartridge. Both the .308 and 6BR chamberings offer good barrel life, but the 6BR uses 15-18 grains less powder, saving you money. Here’s how the 6BR stacks up vs. a number of popular calibers:

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.

Put the same load in a variety of barrels (with the same length and chamberings) and you’ll see a wide variance in muzzle velocity. In fact, it’s not unusual to see up to 100 fps difference from one barrel to the next. We demonstrated this with a comparison test of Lapua factory ammo.

Chron Testing Lapua Factory Ammo
At our Southern California test range some years ago, we chronographed Lapua 105gr 6mmBR factory ammo in three different 8-twist barrels of similar length. The results were fascinating. Lapua specs this ammo at 2790 fps, based on Lapua’s testing with its own 26″ test barrel. We observed a speed variance of 67 fps based on tests with three aftermarket barrels.

Barrel Velocity Variance
Brand ‘S’ and Brand ‘PN’ were pre-fit barrels shot on Savage actions. Brand ‘K’ was fitted to a custom action. All test barrels were throated for the 100-108 grain bullets, though there may have been some slight variances in barrel freebore. With a COAL of 2.330″, the rounds were “jumping” to the rifling in all barrels.

Among the four barrels, Brand ‘PN’ was the fastest at 2824 fps average — 67 fps faster than the slowest barrel. Roughly 10 fps can be attributed to the slightly longer length (27″ vs. 26″), but otherwise this particular barrel was simply faster than the rest. (Click Here for results of 6mmBR Barrel Length Velocity Test).

IMPORTANT: Results Are Barrel-Specific, Not Brand-Specific

These tests demonstrate that the exact same load can perform very differently in different barrels. We aren’t publishing the barrel-makers’ names, because it would be wrong to assume that ‘Brand X’ is always going to be faster than ‘Brand Y’ based on test results from a single barrel. In fact, velocities can vary up to 100 fps with two identical-spec barrels from the SAME manufacturer. That’s right, you can have two 8-twist, 26″ barrels, with the same land-groove configuration and contour, from the same manufacturer, and one can be much faster than another.

Don’t Demand More Than Your Barrel Can Deliver
We often hear guys lament, “I don’t get it… how can you guys get 2900 fps with your 6BRs and I can only get 2840?” The answer may simply be that the barrel is slower than average. If you have a slow barrel, you can try using more powder, but there is a good chance it may never run as fast as an inherently fast barrel. You shouldn’t knock yourself out (and over-stress your brass) trying to duplicate the velocities someone else may be getting. You need to work within the limits of your barrel.

Factory Ammo Provides a Benchmark
If you have a .223 Rem, 6mmBR, .243 Win, 6.5×47 Lapua, 6.5 Creedmoor, 6.5×55, .308 Win, 30-06, or .338 LM Rifle, we recommend you buy a box of Lapua factory-loaded ammo. This stuff will shoot great (typically around half-MOA), and it can give you a baseline to determine how your barrel stacks up speedwise. [Editor’s NOTE: The original test was conducted in 2008. The velocity of current-production Lapua factory ammo might be higher or lower, so your results may vary.]

When you complete a new 6mmBR rifle, it’s definitely smart to get a box of the factory ammo and chronograph it. That will immediately give you a good idea whether you have a slow, average, or fast barrel. Then you can set your velocity goals accordingly. For example, if the factory 6BR ammo runs about 2780-2790 fps in your gun, it has an average barrel. If it runs 2820+ in a 26″ barrel (or 2835 fps in a 28″), you’ve got a fast tube.