X-Ring Newsletter

The X-Ring

Technical Newsletter From Your Ballistic Technicians

Volume 6, Issue 4

Ron Boyd,Marvin Boyd, and Varmint Hunter

Tubb Reigns at
Camp Perry

Tubb Reigns at Camp Perry David Tubb captured his 8th NRA High Power Rifle Championship this August at the National Championships conducted at Camp Perry, Ohio. Tubb used Sierra 6.5mm 120 grain, 140 gr., and 142 gr. HPBT MatchKing bullets at 200, 300, and 600 yards respectively. All bullets were moly-coated with the Tubb/Neco&#reg; process. David's sons Wyatt and Taylor also captured their age divisions at Camp Perry. Ron Boyd,Marvin Boyd, and Varmint Hunter Kent Reeve won the inaugural Sierra Bullets Trophy Match for the aggregate winner of the Doc Aitken Trophy Match and the Ed Andrus Trophy Match. Congratulations Sierra Champions!!
The Big Squeeze
by Paul Box
We've all heard about the problems associated with belted magnum cases. Many shooters get only three or four firings before developing case head separations. The cause for this is excessive sizing; i.e. head spacing the case on the belt. You've sized the case as much as possible and may have pushed the shoulder back farther than necessary. Next time the case is fired it has room to push the shoulder forward to the end of the chamber. This pulls brass out of the web section just ahead of the belt. After only a few firings, the web is thinned enough that a crack forms. There's a better way. Size the case to head space off the shoulder. This goes a long way in preventing this crack. By sizing only enough to provide easy chambering, you'll get better mileage from belted cases.
 

1999 Varmint Hunter
Jamboree in Pierre, SD

Factory Rifle Champion Ron Boyd (left) and Open Class Runner-Up Marvin Boyd (right) are shown with Varmint Hunter Jamboree Range Master Gordy Gitters (center). Ron and his father Marvin both used moly-coated Sierra 6MM 107 grain HPBT MatchKing bullets.

Getting a True Zero
by Paul Box
Countless hunters each year will pin up a target at 100 yards, fire one shot, then make adjustments on their scope. They fire another shot. If it hits anywhere within the targets' bulls-eye, it's sighted in for hunting season. Is it, really? This method may work for the whitetail hunter in heavy timber, but for the hunter with an accurate rifle in open terrain, it isn't enough. Fire at least three shots from a cold barrel. Measure the distance from the CENTER of your group to your aiming point. Make your scope adjustments and fire three more. What we're looking for is the center of our group to be in the center of our aiming point. Want a zero greater than 100 yards, but that's the longest range you have to shoot? Mark a square on a vertical line, the desired distance above the point of aim. When your shots impact within that square, you're set. Accurate zeroing is even more important to the varmint hunter. An error at closer range is magnified farther out, and a crow gives very little room for error. A true zero can make it or break it at long ranges.

A Look Thru
Accuracy Windows
by Paul Box

What's an "accuracy window"? Let's say that with a given rifle, powder and bullet combo that our starting load is 42.0 grains, going up to a maximum of 48.0 grains. We start by firing a group at 42.0 grains, with only fair accuracy. At 43.0 and 44.0 grains, it isn't much better. At 45 things start looking up and 46.0 is better yet. Finally at 47 things really start to perk, while 48.0 starts going the other way. These three combos of 45 gr., 46 gr., 47 gr. are what I call accuracy windows. Naturally we can try fine tuning the loads, but we now have a window of this rifles potential. This is just another way to utilize what our loads are telling us.


Sierra
Handgunner's
Capture Titles
Bruce Piatt, Doug Koenig, and Kay Clark-Mickalec all won major handgun competitions this year while shooting Sierra bullets. Bruce captured the prestigious Bianchi Cup in May. Doug won both the Steel Challenge and The Masters this summer. Kay was the women's champion at the American Handgunner World Shoot Off in Montrose, Colorado. All three world class handgun shooters were using Sierra 9mm bullets.

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