November 16th, 2014

Chuck’s Dazzling Dasher Duo — A Pair of Beauties

Forum Member Chuck L. (aka “Ridgeway”) has created a handsome duo of 6mm Dashers for competitive benchrest and varmint matches in Pennsylvania. Both guns are built on Kelbly Panda RBLP actions, with Bartlein 8-twist barrels, and Shehane Laminated Tracker Stocks. However, the two rifles are not exact twins, as you can see. One, which we’ll call the Big Dasher, is built on a Shehane ST1000 Tracker stock. The other gun, the Small Dasher, sports Shehane’s “Baby Tracker” stock — a design used with great success by Richard Schatz. The Big Dasher, optimized for 1000-yard competition, also has a slightly longer freebore — 0.136″ vs. 0.104″ for the Small Dasher.

6mm Dasher Shehane duo

6mm Dasher Shehane duo

Chuck tells us: “I don’t get out shooting competition as much as I want due to time and family, but when I do compete, I shoot a Groundhog match at Southfork Rifle Club in Beaverdale, PA. Info on Southfork Club events can be found at Southforkrifleclub.com. The Southfork match is basically a 100-, 300- and 500-yard match with one sighter the entire match and 5 shots at each yardage for score. The Small Dasher, with the shorter ‘Baby Tracker’ stock, was set up for the Southfork Rifle Club’s ‘Light Unlimited’ class which has a 13.5-lb max weight.” (Editor: ‘unlimited’ is a misnomer for a weight-limited category.)

Chuck adds: “The Big Dasher with the heavy ST-1000 stock is set up for 1000-yard benchrest matches in Light Gun class. I hope to shoot a couple 1K matches with it at Reade Range in southwest Pennsylvania. I am still in load development for this rifle since it was just finished in January. One ironic thing is, it shoots the same load I’m shooting out of the lighter gun rather well. The only difference between the two chambers is the freebore is roughly thirty thousandths longer on the 1K gun (Large Dasher). I will also shoot this at Southfork in the ‘Heavy Unlimited’ class.”

6mm Dasher Shehane duo

Specifications for the Dasher Duo:

Small Dasher (13.5-pounder): Chambered for 6mm Dasher with approximately .104 freebore and a .264 NK. (No way of knowing exactly since it freebore was done in a separate operation by Kelbly.) Components are: Shehane Baby Tracker stock, Kelbly Panda RPLB action, Bartlein 1:8″ LV barrel at 26 ¾”, Kelbly Rings, Weaver T36, Jewell trigger. The barrel was chambered by Kelblys and the stock was bedded, glued and balanced by a shooting buddy (Forum Member johara1). I clear-coated the stock with auto urethane. Total weight is 13 lbs., 4 ounces.

Big Dasher (1K Light Gun, 17-pounder): Chambered for 6mm Dasher with a .136 freebore and .264 neck (PTG Reamer). Components are: Shehane ST-1000 stock, Kelbly Panda RPLB action, Bartlein 1:8″ HV 5R barrel at 28″, Shehane +20-MOA rings, Nightforce NXS 12-42x56mm, Jewell trigger. The barrel work, pillar installation, and bedding was done by Dave Bruno. The stock was clear-coated by Chuck with auto urethane. Chuck also made the rear butt plate and balanced the rifle. Total weight: 16 lbs., 13 ounces.

Dasher Case-Forming: Neck-Turn then Fire-form with Bullets Hard in Lands
To fireform, I turn my cases down to fit the chamber and stop where the false shoulder makes snug contact with the chamber. Fire-forming rounds are loaded up with a 29-grain charge of H4895 or Varget and a 108gr Berger bullet seated hard into the lands about 0.020″ past initial contact with the rifling. It takes about three firings to make a nice clean Dasher case with a sharp shoulder. I anneal about every 3-4 firings. I have many cases that have about 10+ firings on them and they are still shooting well. The primer pockets are a little looser, but still hold a primer.

6mm Dasher case fire-forming fireform

Both Dashers Group in the Ones at 100 Yards
My main bullet for both rifles is the 107gr Sierra MK, loaded with Reloder 15 powder, Lapua cases and CCI 450 primers. My main load for the Small Dasher is 33.0 grains of Reloder 15. This load shoots in the ones at 100 yards. For the Big Dasher, I’m still working on a load, although the same 33.0 grain load shoots in the ones in the heavier gun as well. I’m still looking for more velocity and my ‘max’ node. So far, I’ve gone well above 33.0 grains of RL 15 without pressure signs, but that load produces vertical at 100 yards, so I’m going to tinker with the load until I see pressure or it starts to shoot.

Permalink Gunsmithing, Hunting/Varminting 4 Comments »
November 16th, 2014

Advanced Reloading: Controlling Cartridge Powder Column Height

Most of us assume that if we weigh our powder carefully (down to the tenth of a grain or less) we can achieve a uniform powder fill from case to case in our handloads. Weighing does ensure that the weight of the propellant in each case is the same, but is the column of powder the same by volume each time? “Not necessarily” is the answer. An interesting experiment by our friend Boyd Allen demonstrates that the manner in which you place kernels in the case can make a significant difference in the height of the powder column within the brass case.

Using a Gempro 250 scale, Boyd measured exactly 30.6 grains of Vihtavuori N-133 powder. He then inserted this powder in the same cartridge case multiple times. (The case has a fired primer in place.) But here is the key — Boyd used various filling techniques. He did a slow fill, and a fast fill, and he also experimented with tapping and drop tubes. What Boyd discovered was that you can start with the exact same weight of powder (in fact the very same set of kernels), yet end up with vary different fill heights, depending on how you drop the kernels into the case. Look at the photos. Despite variations in lighting, the photos show the same 30.6 grains of powder, placed in the same cartridge, with four different methods.

Boyd Explains the Procedure Used for his Experiment.

EDITOR’s NOTE: So there is no misunderstanding, Boyd started with a weighed 30.6 grain charge. This identical charge was used for ALL four fills. After a fill the powder was dumped from the case into a pan which was then used for the next fill technique to be tried. So, the powder weight was constant. Indeed the exact same kernels (of constant weight and number) were used for each fill.

Boyd writes: “I used the same powder for all fills, 30.6 gr. on a GemPro 250 checked more than once. All fills employed the same RCBS green transparent plastic funnel. The fast drop with the funnel only overflowed when it was removed from the case neck, and 15 granules of powder fell on the white paper that the case was sitting on. The fast-funnel-only drop with tapping, was done with the funnel in place and the case and funnel in one hand, while tapping the case body with the index finger hard, many times (about 20 fast double taps). My idea here was to “max out” the potential of this tapping technique.

The slow drop with the funnel and 10″-long .22 cal. Harrell’s Precision drop tube, was done by holding the scale pan over the funnel and tapping the spout of the pan repeatedly on the inside of the funnel about 1/3 down from the top, with the scale pan tilted just enough so that the powder will just flow. Many taps were involved, again, to max out the technique.

Again, to be clear, after each case filling, the powder was poured from the case back into the scale pan carefully. You may notice the similarity between the fast drop with the drop tube, and the funnel only with tapping. Although I did not photograph it, fast tube drop and tapping (combined) improved on tapping alone, but only to about half as far down the neck as the slow with drop tube. Due to the endless possible permutations, I picked four and left it at that.

I believe that I can make the rough judgment that the scale pan funnel and drop tube technique, which involved a longer drop period, and probably less velocity at the top of the tube, left more room in the top of the case neck than the slow drop from the measure with the same drop tube. You have both pictures, so you can make the comparison.” — Boyd

Does Powder Column Height Variance Make a Difference?
Boyd’s experiment proves pretty conclusively that the method of dropping a given weight of powder can affect the height of the powder column in the case and the degree of powder compression (when a bullet is seated). He showed this to be true even when the exact same set of kernels (of constant weight) was used in repetitive loadings. This raises some interesting questions:

1. Will subsequent cartridge transport and handling cause the powder to settle so the variances in powder column height are diminished?

2. If significant inconsistencies in powder column height remain at time of firing, will the difference in fill level hurt accuracy, or result in a higher extreme spread in velocity?

3. Is there any advantage (beyond increased effective case capacity) for a tight (low level) fill vs. a loose (high level) fill?

We don’t know the answer to these follow up questions. This Editor guesses that, if we tested low-fill-height rounds vs. high-fill-height rounds (all with same true fill quantity by weight), we might see meaningful differences in average velocity. I would also guess that if you fired 10 rounds that exhibited quite a difference in powder column heights, you might see a higher ES/SD than if you shot 10 rounds loaded with a very consistent powder column height (either high or low). But further testing is needed to determine if these predictions are true.

Permalink Reloading, Tech Tip 5 Comments »
November 16th, 2014

Motivational Advice from Eley’s Champion Shooters

Eley sponsors many of the world’s top rimfire shooters, who have shared their Tips from the Top for 2014. Five ace smallbore shooters provide advice on how to shoot better, how to train more effectively, and how to stay motivated even when “the going gets tough”. If you’re a competitive shooter (in any discipline) you can benefit from reading these words of wisdom from world-class shooters.

Eley champions shooting tips

Henri Junghaenel, current world #1 ranked, 50M prone rifle shooter.

    Focus on Fundamentals: Good performance requires a solid technical foundation. One can hunt after personal bests or one can try to work on the technical basics. The latter will probably lead to better results sooner.

    Stay Motivated Over Time: Be persistent and don’t lose your motivation on your way to success. Shooting, like every other sport, requires a learning process which takes a lot of time.

    Don’t Yield to Outside Pressures: Don’t let the expectations from others impact yourself. If some people try to put pressure on you (consciously or unconsciously), don’t let them!

Bill Collaros, 2013 Australian WRABF World Cup (Benchrest) and RBA team captain.

    Don’t Skimp on Hardware: Ensure your equipment is a good as you can buy. This includes: rests, bags, rifle, scope, and ammunition.

    Tune to Your Ammo: Ensure that the ammunition you have is tested and your rifle is tuned to it, to get the smallest possible group.

    Train in All Conditions: Train in all sorts of wind and conditions so you know how your rifle and ammunition react in all circumstances.

Stine Nielsen, 2012 Olympic finalist for 3-Position Smallbore Rifle.

    Eley champions shooting tips

    No Excuses: When I train, I train by my motto: “A loser has excuses. A winner has a plan.” And when I shoot in competitions I think about that mantra.

    Stay Focused: When I stand at a shooting range, I have a good focus on my shooting and myself. I also have a good will to want to shoot 110%.

Zorana Arunovic, current world #2 ranked, 25M women’s pistol shooter.

    Never give up: No matter how hard it is you should always find something that will inspire you to keep going further. I find my inspiration in the success of other athletes. They inspire me to work more and harder. I would say to any young athletes, never give up, no matter how hard it is.

João Costa, current world #2 ranked, 50m pistol shooter.

    Breathing is Key: In shooting as in life, breathing is of paramount importance. So, when shooting try to be calm and quiet. On the bench in front of me I have my pistol, the scope, the magazine and my choice ammo then I count:

    1… Eley – breathe
    2… Eley – breathe
    3… Eley – breathe
    4… Eley – breathe
    5… Eley – breathe

Story find by EdLongrange. We welcome reader submissions.
Permalink Shooting Skills No Comments »