March 31st, 2017

500-Round Group at 300 Meters — Now That’s a Test!

Sierra Bullets 500 round tunnel test

For load development, some guys shoot 3-shot groups. Other guys shoot 5-shot groups, or even 10-shot strings. But for testing its projectiles, Sierra Bullets takes it to another level entirely. A while back Sierra was testing its .30-Caliber 175gr HPBT MatchKing in the Sierra uynderground tunnel. The results are show above — a FIVE HUNDRED Round group!

The tunnel testers sent five full boxes of bullets down-range. Here are 500 Shots shot in a 300 meter tunnel. The group size is 2.82 inches (that’s edge to edge of the farthest shots, less the bullet diameter). This was a pressure/velocity test for a commercial customer. The Cartridge was .308 Win, loaded at 2.800″.The powder was Reloder 15. A 26″ barrel was shot from a return to battery rest. The gun was cleaned every 125 rounds and two foulers shot.

What do you think — could you beat this group from a bench for 500 rounds?

One Facebook poster joked: “500-round group? Everyone knows anything less than 1000-round groups are a waste of time and statistically irrelevant.”

Sierra Bullets Test Tunnel Barrels

Sierra’s 300 Meter Testing Tunnel
Ever wonder how (and where) Sierra tests its bullets? The answer is underground, in a 300-meter test tunnel located under Sierra’s factory in Sedalia, Missouri. The photo above shows the construction of the tunnel back in May, 1990. Like most bullet manufacturers, Sierra does live-fire bullet testing of its projectiles. Sierra’s 300-meter test range is the longest, manufacturer-owned underground bullet test facility in the world. Sierra offers free tours of the test tunnel as part of Sierra’s Factory Tour Program.

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March 31st, 2017

How Scopes Work — Understanding Lenses and Light Paths

Accurateshooter.com optics rifle scope Swarovski

The Swarovski Optik website features a blog with interesting technical articles. In the “On Target” series of blog stories, Swarovski has provided a handy explanation of how optics systems work, with exploded diagrams of rifle scopes, spotting scopes, and binoculars. CLICK HERE for Swarovski Optics Blog.

Accurateshooter.com optics rifle scope Swarovski

Scope Terminology
Focusing Lens
The focusing lens is an adjustable lens inside the optical system for focusing the image at different distances…. In the case of rifle scopes, apart from focusing, the focusing lens also facilitates parallax compensation.

Diopter Adjustment
For rifle scopes, the reticle can be focused using the diopter adjustment on the eyepiece, thereby correcting any visual impairment. [Editor’s Note: Movable eyepiece diopter adjustment is not offered on all rifle scopes. It is a useful feature on Swarovski and other premium scopes. This allows shooters who need eyeglasses to get a sharply focus image even without wearing corrective lenses. Of course shooters should always wear ANSI-certified eye protection. With the diopter, folks who need correction can use inexpensive, non-Rx safety eyewear instead of expensive prescription safety glasses.]

Reversal System
The purpose of the reversal system is to reverse the image by means of prisms in binoculars and telescopes, and lenses in rifle scopes….The lens reversal system is needed in rifle scopes to control the variable magnification and move the exit pupil[.]

Parallax Explained
What is Parallax? What problems can Parallax create when you are shooting? Many novice shooters can’t answer those questions easily. Likewise, many folks don’t understand how to use their front or side-focus parallax controls most effectively. Yes the parallax control basically sharpen focus at different target distances — but there’s more involved. This video offers helpful insights.

Resource tip by EdLongRange. We welcome reader submissions.
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March 31st, 2017

Enhance Mental Function to Shoot Better Scores

Shooting Sports USA Brain mental game psychology cerebellum

Looking to improve your competition skills? The Shooting Sports USA website has scores of informative articles that can help your score higher at your next shooting tournament. You’ll find articles on wind reading, position shooting, match strategies, and much more.

One great Shooting Sports USA article, Shooting is 90% Mental, was penned by Chip Lohman (SSUSA’s former Editor). With the help of two very smart Ph.D types, Judy Tant and Mike Keyes, Lohman examines the mental processes involved in the shooting sports. Chip’s co-authors have impressive credentials. Dr. Judy Tant is a Clinical Psychologist and National Bullseye Pistol Champion. Dr. Michael J. Keyes, is a licensed Psychiatrist and former physician for the U.S. Shooting Team.

CLICK HERE to Read Full Article in Shooting Sports USA Online Magazine.

Visualization, Brain Function, and Muscle Memory
If you shoot competitively, this is definitely a “must-read” article. The authors examine how the brain functions under stress, how “visualization” can be used to improved performance, how “brain speed” can be enhanced through proper training, and how the brain stores learned routines into “muscle memory.” And that’s just for starters — the article gives many concrete examples of techniques top shooters have employed to improve their “mental game” and shoot higher scores.

Brain Speed and Trigger Control:
Shooting Sports USA Brain mental game psychology cerebellumResearch: Scientists believe that the newer frontal lobe may not be able to keep up with “deep” brain signals that transmit at nearly 300 mph. This is explained when athletes talk about “letting go,” rather than over-thinking the shot. This conscious signal can take up to 0.3 seconds from recognizing the desired sight picture to moving the trigger finger — too long to capture the opportunity for a perfect shot. However, if the signal is initiated spontaneously in the cerebellum where such procedures are thought to be stored through repetition, the reaction speed is much quicker. Signals are processed by the “deep brain” almost twice as fast as the problem-solving frontal lobes.

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