A Rifle for the Long Shots – The 6mm Dasher

©By Glenn Burroughs

There was once a publication titled Varmint Hunter Magazine and it included a section called ‘Member Photos’. Many of the pictures were of shooters who had been inducted into the magazine’s Long Range Club, a club that honored those who struck pay dirt by eliminating a varmint at a distance of 500 yards or more. Almost unbelievably, there were some who made successful, and verified, shots out to 2500 yards. For their accomplishments they received a nice certificate suitable for framing.

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View of right side of rifle.


For quite some time I wanted to qualify for the Long Range Club by driving out west and making a one thousand yard shot on a prairie dog. It would give me the perfect award to hang in the reloading room next to my “Fastest Gun in Hogtown” plaque. But with no warning the magazine, and along with it the Long Range Club, closed shop. I was somewhat depressed and dropped the idea.

But life goes on. A few months later while conversing with a friend from Pennsylvania he said he might be able to provide me a long shot at a groundhog, maybe even a thousand yard shot. That boosted my morale considerably… after all, a trip to Pennsylvania is a lot shorter than a trip to Montana, and a groundhog is a considerably larger target than a prairie dog. Well, the motivational flames were relit and my enthusiasm was kicked up a bunch of notches.

Connecting with a varmint at a thousand yards, or anywhere close to that distance, would be quite an accomplishment. In fact, there are some who think it’s not possible to hit something as small as a prairie dog at that distance, and go so far as to say there is some stretching of the truth involved with these claims. As one shooter told me, “You can’t even see a prairie dog that far away, so how can you hit it?” A good point, but a trip to any 1000 yard match would put the matter to rest. It is not uncommon for these competitors to put ten shots in a six inch group, and this accuracy would easily take care of a small varmint.

But to achieve this deed requires a very accurate rifle, a good shooter, premium ammunition and catching Mother Nature in a good mood. Before attempting this goal two major hurdles would have to be overcome: obtaining a rifle capable of the task and finding somewhere to practice at considerably longer distances than the local 300 yard range… the mountains and rolling hills in south-central Virginia do not offer many opportunities for long shots. Obviously the most important of the two requirements would be the rifle, and this required a decision on which cartridge would be best for the job.

Every shooter has their reasons for choosing what they believe to be the ideal long-range cartridge, and these choices are many and varied. My method was fairly simple. A little investigation indicated that the most popular calibers for thousand yard shooting were the 6mm, 6.5mm and 30-calibers. And, according to one source, the 6mm Dasher has set more records at 600 and 1000 yards than any other round.

Further examination into the Dasher brought up several rather impressive bits of information… in 2014, Jim Richards, shooting at the Deep Creek Range near Missoula, Montana, set a world record with his 6mm Dasher by placing ten shots in a 2.6872-inch group at a thousand yards. And he was shooting in the Light Gun class. At the 2015 IBS 600 yard Nationals Richard Schatz took first place in the two gun category with his Dasher, and notably, seventeen of the top twenty competitors were shooting 6mm Dashers. Not surprisingly, a search on the internet will bring up a myriad of cases where the Dasher has set another record.

Curious to learn more about the history of the Dasher I contacted the originator and well-known gunsmith, Dan Dowling. It was around the year 1999 when Dan and his friend Al Ashton, came up with the 6mm Dasher. The name of the cartridge was derived from the names ‘Dan’ and ‘Ashton’. Using a 6mm BR case the body was lengthened and given a forty degree shoulder and a shorter neck. The Dasher offers about ten percent more case capacity than the standard 6mm BR and provides an extra 130 feet per second velocity with a 105 grain bullet.

Dan said the cartridge was first made in 22 caliber and the first ‘cut’ of the 6mm Dasher went to Al Ashton. The second 6mm Dasher went to Richard Schatz in Bismarck, North Dakota. Dan said Richard was the one who got the Dasher going. Richard was reading a copy of Precision Shooting Magazine in the fall of 1999 and saw an article about the then-new 6mm Dasher. Richard gave Dan a call, and after putting together the components, Dan went to work. In January 2000, the gun was completed and Richard Schatz had the second 6mm Dasher rifle ever created. The Dasher was on its way.

It would have been nice to build my Dasher from scratch starting with a custom action, but that was out of the question… funds for this venture were minimal. After mulling over the situation it was decided the least expensive route would be to take one of my least-used target rifles and replace the barrel. Although not inexpensive, this option only required a barrel, a reamer and some first-rate gunsmithing.

The rifle selected for the project was based on a Savage Model 12 Target action; a right-bolt, left-load, right-eject, dual port action that included the competition version of the Savage AccuTrigger. This trigger can be adjusted down to six ounces and breaks as clean as a thin glass rod. The action had been completely worked over by Mark Penrod of North Manchester, Indiana, and in his words: “The action was inspected for true surfaces, including the thread straightness. The threads were straight and needed no adjustment. The receiver face was machined square to the axis of the bolt. Two modifications were made to the bolt; the bolt head was machined square to the axis of the bolt and lapped-in with the receiver lugs. The recoil lug was surface ground flat, then de-magnetized.” When the rifle was returned a Nightforce 10-42X BR scope with a 20 MOA base was mounted on the rifle. The Nightforce has a maximum adjustment of 40 MOA and with a 20 MOA base, is ample for a thousand yards.

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View of left side of rifle.


The Savage action rested in a Mike Koontz stock made from blue and black laminated birch. The forearm was given the maximum width of three inches and the bottom of the stock was sloped slightly from the pistol grip to the recoil pad in the event the rifle might be used in benchrest matches. From the three inch base the stock quickly curved up to a width of two inches and flutes were cut down the sides. The three aluminum action pillars were bedded in Marine Tex. The finish required four coats of clear, each coat sanded, then buffed with a swirl remover followed by an application of Mother’s Carnauba wax. The stock was finished off with a rubber Pachmayr Decelerator recoil pad that would soften some of the kick.

Selection of the new barrel was easy… most of my custom rifles have Krieger barrels and I tend to favor this brand when having a varmint or target rifle put together. Not only are Krieger barrels very accurate and long-lasting, they are very easy to keep clean… a trait that seems to go along with a cut-rifled barrel, and an attribute that I have come to enjoy immensely. So an order was placed with Krieger for a stainless 6mm barrel, one with a 1:8-inch twist to handle the 105 grain bullets.

The reamer specifications were obtained from a friend who was taking up 1000 yard competition and his 6mm Dasher was built by a noted gunsmith… one who specialized in long range rifles. I figured this reamer would be ideal so an identical one was ordered from Dave Kiff of Pacific Tool and Die.

After the order was in the mill for some time a most interesting note arrived from Dave: “In its short life the Dasher has held many match, team, state and world records. I think from my records the Dasher and the 6.5-284 are close to the dominate chambers at 600 yards. The .150-inch free-bore you selected is great for 115-grain bullets. The records are held with .104-inch and .112-inch free-bore using 105 and 107 grain bullets. One of the world records was set with Hornady 105-grain bullets touching a .104-inch free-bore.”

Dave is an excellent source for knowledgeable advice on reamers, chambering and the finer details for accuracy that often prove so valuable. It did not occur to me at the time, but Dave would have been the logical place to determine the best reamer specification to meet my requirements. Next time I will know better.

A Rifle for the Long Shots – The 6mm Dasher

The next task was to determine the best method for making the brass. The typical reshaping of a case using forming dies was not an option for the Dasher since the shoulder is longer than its 6mm BR parent case… not shorter like many wildcats. Investigation showed that Dasher cases were being devised in several ways. What appeared to be the most popular was to open the neck of a 6mm BR case with a .257 caliber or 6.5mm expander, then size the case neck about half-way down, leaving a ‘donut’ on the outside of the neck to headspace the cartridge. The cartridge is then chambered and fire-formed.

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View of the Dasher with 300-yard targets in the distance.


Another often used method is to take a standard 6mm BR case and, using a bushing-type sizing die, size it such that the neck will have heavy tension on a seated bullet. The bullet is then seated into the lands and fired with a near full-power load. This method is certainly the easiest and has the advantage of not working the neck of the brass. In any case, a lot of barrel-burning is required with either of these methods to get the final product.

It was on a trip to the IBS 1000 Yard Nationals where I learned about a new type of forming die… at least it was new to me. Visiting the Hornady Manufacturing booth I mentioned my interest in the 6mm Dasher, and asked which fire-forming method they would recommend for making cases. One of the techs smiled and said, “Neither. Why don’t you use one of our hydraulic dies?” Then he described how it worked and showed me some brass he was using in the match… it was a wildcat cartridge he and Dave Kiff of Pacific Tool and Die had designed. He compared it with a case that had just been through a hydraulic die, and one would have to look closely to see the difference. With that demonstration I was sold on the concept.

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Hornady hydraulic die. Case on left is standard 6mm BR and case on right is after re-sizing in the hydraulic die.


After returning home Ben Syring, Hornady’s custom die designer, was contacted. He advised that the various specifications for the Dasher are so similar between reamers that Hornady carries a standard set of regular dies and a standard hydraulic die. After a most enlightening discussion the hydraulic forming die was placed on order, along with a set of Hornady Match reloading dies.

During my Dasher research the use of Lapua 6mm BR brass to make the Dasher case was mentioned almost exclusively so I gathered up two hundred rounds. The cases were prepared by first seating spent primers in the unfired Lapua 6mm BR cases. Although obvious, it is imperative to insure the primers have been fired and the firing pin dent has not punctured any of the primers (as this would allow water to leak out of the case).

Each case was then filled to the very top with water and placed in one of Sinclair’s poly loading blocks. Next, the special Hornady shell-holder was slipped into the ram of the press. This shell-holder is similar to a standard version except it does not have a hole for primer service, otherwise the hydraulic pressure would drive the primer out of the case and through the hole in the shell-holder. Once the shell-holder was in place the hydraulic die, complete with die rod, was mounted in the press and adjusted so the base just touched the shell-holder.

To create a Dasher case a water-filled 6mm BR case would be retrieved from the block and the outside dried with a paper towel. Before inserting the case into the press each case was checked to insure it was full of water with no leaky primer. Once the case was in the press the handle was pulled down to move the case up into the die.

With the press handle held steady with one hand, the hydraulic piston (or ram) on the die was given several raps with a dead-blow hammer, making sure the hammer hit the piston directly on the top center. Finally, the case was removed, emptied of water and set aside. Once all cases were formed the spent primers were removed and both the cases and the hydraulic die were dried. That’s all there was to it… and no bullets, powder, primers or barrel wear was required. The results are cases that look very nearly like they have been fire-formed. A little over an hour at the press provided a hundred cases.

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Left to right, 6mm BR Norma case, after hydraulic die forming, and a fire-formed 6mm Dasher.


The Savage rifle, along with the Krieger barrel and PTG reamer, was delivered to Eddie Webster, a top-flight gunsmith from Boones Mill, Virginia who put together a nice 22 PPC varmint rifle for me a few years ago (This very accurate rifle was the topic of an article in the Summer, 2013 issue of Varmint Hunter Magazine). A month or so after the rifle was dropped off at his shop Eddie called to let me know the Dasher was ready, so I headed for Boones Mill.

Eddie met me as I drove up and we went in his shop to examine my ‘new’ rifle. As he handed me the rifle he commented, “Whoever did the work on the action did an excellent job, I gave the action a thorough check and no accuracy work was required.” When asked what he had done Eddie replied, “I did my typical barrel installation for a bench rifle; the contour on the Krieger barrel was machined, then chambered and threaded, then the barrel crowned. After I was satisfied things were as good as they could be I test fired it at the range. Only had a few rounds so I could not start developing a good load.” The craftsmanship was typical of Eddie’s work; beautifully done. After our chat, and with a smile on my face, I took the Dasher and headed back home.

For a reasonable chance at a successful thousand yard shot I estimated the rifle should be able to shoot one inch groups at three hundred yards. Of course the shooter would have to do his part, and not being an expert at adjusting for wind or mirage, I would be the weak link in the chain. The initial load development would be using a bullet well known for its accuracy, the Hornady 105 grain A-Max.

These projectiles are reasonably priced, have proven to be very accurate and hold several long range records. In fact, several years ago Kyle Brown set a new 1000 yard world record for ten shots with a 4.2-inch group, and he was using Hornady’s 105 grain A-Max. At that rate Kyle might have gotten eight or nine prairie dogs with those ten shots. The general consensus is that Varget, Reloader-15 and H-4895 are three of the most popular powders for the 6mm Dasher. At the time only Reloader-15 could be located, but that was no problem as this powder was used to set a thousand yard world record with the Dasher.

On the first trip to the range, several fouling shots were executed followed by the first A-Max group at a hundred yards. It measured .275-inch, what I thought was a good omen. Over the period of several months load development continued, trying different powder charges and seating depths. The A-Maxes were averaging .409-inch at a hundred yards and 1.554-inch at 300 yards, good performance but I thought the rifle should do better. Don Lahr of Precision Ballistics was contacted and we discussed the goal of one inch groups at 300 yards. As expected Don was very interested in the challenge and said he would send me some 105 grain VLD bullets that “should do the job”.

When the bullets arrived there was a note enclosed: “I used the thick wall J4s, and the seating went exceptionally well by using just the perfectly sized seating punch, so the center of gravity should be very consistent for them all. The bearing lengths are all plus or minus 0.015-inches and the weights are all plus or minus 0.1 grain. I burnished the tip of every bullet with a finger nail buffer/shiner to remove any rough edges from the tooling and polish them. They should be very aerodynamic, concentric, balanced and uniform. In my humble opinion, these bullets are capable of groups two inches tighter at 1000 yards than out-of-the-box factory competition bullets. You should be able to shoot 2½-inch or smaller groups at 1000 yards. My rifles agree, as do reports from hundreds of my customers, that they prefer a seating depth jammed between 0.005 and 0.010-inch, with most doing best at 0.007-inch. Of course your gun may differ, but that should be a very close starting point. I’m confident that my bullets will not be the weak link in the chain for your trial.”

Testing was begun with the 105 grain Precision Ballistics bullets and continued over a period of several weeks. All manner of bullet seating depth was tried but accuracy was just slightly better than the A-Max bullets. Then one evening while scanning the internet I read about someone having problems setting an accurate bullet seating depth for ‘jamming’ because the case neck tension was too loose… this allowed the bullet to slide back into the case when chambered. That immediately rang a bell with me. A quick test of the bushing in the Dasher sizing die showed it would not hold a bullet snug enough to jam a bullet into the lands. There was no way of knowing how deep the bullets had been seated on my loads, so the last several weeks of testing had been for naught.

My morale was rather low at this point so I called Eddie Webster to discuss my woes. After listening to my tale, and with his normal enthusiasm, he commented, “I think the reamer we used has too much free bore for 105 grain bullets. Let’s return the reamer to Pacific Tool and Gauge and have them regrind it based on Dave Kiff’s recommendation. I’ll re-chamber the barrel with the new reamer… I think we can get it shooting the way you want it.”

Again my morale was elated, how could I turn down an offer like that? We set up a time to meet at Hardee’s restaurant, halfway between his place and mine. We had a cup of coffee, a biscuit and spent some time discussing the project. After the enjoyable session Eddie left with the rifle and I headed home with an optimistic outlook.

While the rifle was at Eddie’s the brass and reloading equipment were checked thoroughly. Although the case length variation within the Lapua cases was only 0.002-inch, they were all trimmed to 1.534-inches, then chamfered and de-burred. The flash holes were checked… each had been cleanly punched out. Just to be sure, they were touched up lightly with an RCBS flash hole de-burring tool. Each case was then weighed, with the result showing a weight variation of less than two grains… no sorting was needed.

The dies were checked and cleaned. The Hornady sizing die bushing was 0.263-inch; this would size the neck such that the inside diameter of a case neck would be 0.02-inch less than the bullet diameter, insuring the bullet would be pushed into the lands during the seating operation. The Forster Micrometer seating die was also checked and the results verified with a Hornady Lock-N-Load gauge… the bullets would be seated exactly 0.007-inch into the lands. Some test ammo was then loaded and set aside, awaiting the return of the rifle.

A Rifle For the Long Shots the 6mm Dasher

It was just a few months later when Eddie sent an email that included an attached photo. The email simply read, “This is a 3 shot, 100 yard group.” The photo showed a target that had one hole, dead-center in the bulls-eye. Needless to say I was soon on the way to Boones Mill to pick up the Dasher, and then head home and back to the range.

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Eddie Webster’s target.


The next batch of test rounds had already been loaded, two three-shot groups with each of five RL-15 powder weights: 31.0 grains, 31.5 grains, 32.0 grains, 32.5 grains and 33.0 grains. Upon arriving at the range a bench was selected and the front rest was put in place. The rear rest was added and the rifle snuggled into the arrangement. It was time to settle down and see what the new chambering had to offer.

The targets normally used for 300 yards are designed for 100 yard use and are somewhat small, with six bulls-eyes on a standard sheet of paper. But the supply had been depleted and the only targets available had one bull on each page… a very large diamond shape rhombus. After the targets were hung at 300 yards I moseyed back to the bench and settled down to shoot.

When I took a look through the Nightforce scope one word came to mind... “Wow!” That big rhombus target allowed my ageing eyes to precisely place the crosshair exactly where it belongs. This allowed me to adjust the crosshairs much more precisely than the smaller targets I had been using, and perhaps to shoot the rifle more accurately.

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First group at 300 yards with new chambering.


It felt good to be behind the butt plate of the Dasher again, looking through that clear Nightforce glass. With a light breeze and no mirage the shooting began, and when the dust had settled the two groups with 31.0 grains of powder averaged 0.745-inches (the first group was .288-inches). The others, in ascending order were 0.849-inches, 0.764-inches, 2.466 inches, and 1.543-inches. This was quite a pleasant surprise, one that had not been expected. The first three loadings had bested the goal of an inch group at 300 yards.

The primary requirement for making a very long shot on a varmint was now in hand… a rifle capable of doing the job. Now the long-range practice begins, followed by a trip to somewhere with wide open spaces and roaming varmints. The wheels are in motion.

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Glenn at the bench with the 6mm Dasher.



Hogtown note: Madison Heights, Virginia lies just across the James River from Lynchburg. In the early part of the last century it was illegal to raise pigs in Lynchburg, so the folks in Madison Heights took up the chore. For their effort the area was awarded the stigma of ‘Hogtown’. Many years later a gun club situated just outside of Madison Heights held Cowboy Action matches, and the shooter with the fastest times with a six shooter, lever action rifle and double barrel shotgun was awarded a plaque noting the deed.


(Neither the writer nor the publication accepts any responsibility for the safety of loads mentioned herein in other firearms. They were safe in the firearms mentioned and on the day of their firing. Start with minimum safe loads and work slowly up.)


Contacts

Don Lahr, Precision Ballistics LLC (bullets)
360 E. Paradise Hills Dr.
Henderson, NV 89002
Phone (702) 331-1337
www.precisionballisticsllc.com

Eddie Webster (gunsmith)
W&M Gun Repair
3607 Alean Road
Boones Mill, VA 24065
Phone: (540) 420-0795
Email: [email protected]

Graf & Sons, Inc. (Lapua Products)
4050 South Clark
Mexico, MO 65265
Phone: (800) 531-2666
www.grafs.com

Hornady Manufacturing Co. (Dies and bullets)
Box 1848
Grand Island, NE
Phone (800) 338-3220
www.hornady.com

Krieger Barrels, Inc. (Cut-rifled barrels)
2024 Mayfield Rd
Richfield WI, 53076
Phone (262) 628-8558
www.kriegerbarrels.com

Mark Penrod - Penrod Precision
312 College Avenue
N. Manchester, IN 46962
Phone (260) 982-8385
Email: [email protected]

Nightforce Optics, Inc.
336 Hazen Lane
Orofino, ID 83544
Phone (208) 476-9814
www.nightforceoptics.com

Pacific Tool & Gauge, Inc. (Reamers and gauges)
598 Avenue C
White City, OR 97503-1031
Phone: 541-826-5808
www.pacifictoolandgauge.com

Sinclair International (Shooting supplies)
200 South Front Street
Montezuma, Iowa 50171
Phone: (800) 717-8211
E-mail: [email protected]
www.sinclairintl.com


Glenn Burroughs is a retired computer systems manager with a lifelong love of guns. His main areas of interest are accurate rifles, wildcat cartridges, reloading and bench shooting. He also enjoys an occasional trip out west to the prairie dog country. Glenn was a columnist for Precision Shooting magazine and also wrote articles for Varmint Hunter magazine. He resides in Lynchburg, Virginia.