Recent Press Releases
in Shooting Times, The Varmint Hunter, Precision Shooting and VHP Magazine
Cartridge concentricity is fundamental to accuracy; lack of concentricity is measured as "run out." Handloaders rarely create loads showing less than two-thousandth-inch (2/1,000") bullet run out – misalignment between axis of bullet and axis of case. Such misalignment inevitably results in some damage to the bullet and increased barrel vibrations, which diminishes potential intrinsic accuracy. The slightly deformed projectile enters the barrel on angle. The thereby provoked rotational imbalances of the bullet in and after leaving the barrel lead to an unwanted enlargement of the target group.
Run-out occurs, despite precise use of the best handloading equipment available. Moreover, only rarely do factory-loaded cartridges show less than ten-thousandths-inch run out.
For various reasons, concentricity-measuring devices that have formerly been marketed are of limited value:
  • Most are difficult to use correctly. Most users have difficulty adjusting these tools precisely, to achieve the most reliable measurement.
  • Use-to-use variations in tool set up alter run out reading and limit precision of measurements taken.
  • Some of these tools are rather delicate.
  • There is no option of improving the cartridge by adjusting concentricity.
As a result, measurements taken are rarely as accurate or repeatable as the user might hope. Moreover, none of these tools offers any means whereby the user can accurately remove run out and thereby correct bent cartridges.
BERSIN GMBH, a precision measuring company located in Switzerland, has recently developed and patented a measuring and adjustment device (now manufactured in the United States). This tool allows the serious marksman to assess cartridge concentricity, with accuracy closer than one-thousandth-inch. More importantly, it allows the user to adjust loads having bent case necks, to practically eliminate run out.

The heart of this tool is a pseudo cartridge chamber, which provides cartridge fixation within the main body of the tool – center in photograph. With the longitudinal axis of the case fixed, the user tests bullet run out by turning the case. Any such run out is indicated on the precision dial indicator – left in photograph. Adjustments, to bend the case shoulder, and thereby reduce bullet run out, are achieved by turning the large knob – right in photograph. With most cartridges, users can become proficient at this process in a matter of a few minutes and thereafter straighten any given cartridge within a few seconds. Intensive independent testing has shown that cartridges straightened with this tool shoot much more accurately; often groups fired with straightened cartridges are only one-half the size of those fired with as-loaded cartridges!
The BERSIN tool is easy to learn and fast to use. It provides 100% repeatability. While measuring and adjusting concentricity, dial indicator reading simultaneously reflects seating depth uniformity. In addition, dimensional flaws on bullet and case will show as erratic fluctuations in indicator reading, as the user turns the case.
These devices are case specific and double-ended. Each tool does two types of cartridges. The BERSIN tool achieved great success and wide acceptance in its first year of availability in Europe. U. S. sales began in 2003.
Reports from Benchrest Competitors and Varmint Hunters are very positive. Tool sizes now offered cover many of the most popular standard chamberings, from 17 Remington up to 50 BMG; recommended retail price, $219 -- $259, depending upon tool size and dial indicator units (2/10,000” to 4/10,000”). BERSIN also offers a kit accommodating most popular current chamberings, from 17 Remington through 340 Weatherby Magnum; suggested retail price, $279. See brochure or website information for details.
This device is ideal for both the handloader and factory load shooter. For more information, please make contact through WWW.BERSIN.INFO, or BERSIN GmbH, 30 St. Jakobs-Strasse, CH-4002 Basel, Switzerland, or BERSIN@BERSIN.INFO.
 

 

 

Article
Published in The Varmint Hunter 2004-1 and Precision Shooting April 2004
     

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Article
Published in VHP Magazine 2004-03 issue
     
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