Sunday GunDay: 6mm Dasher F-Classer — Winning Budget Build

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.