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20 °C —A Short History of the Standard Reference Temperature for Industrial Dimensional Measurements


Subdeacon Joe

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Ya know... that's all cool and all. But I think you'll find this to be more relevant to Cowboy Action Shooting, the Saloon (ACS!), and life on the prairie in general. :)

 

Maxwell's Equations

 

;)

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Ya know... that's all cool and all. But I think you'll find this to be more relevant to Cowboy Action Shooting, the Saloon (ACS!), and life on the prairie in general. :)

 

Maxwell's Equations

 

;)

Oh, the contrary, the article referenced in the base note points out how important it is to control the environment in you loading room to assure that the temperature is precisely 20°C lest you get imprecisely sized cartridges.

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Oh, the contrary, the article referenced in the base note points out how important it is to control the environment in you loading room to assure that the temperature is precisely 20°C lest you get imprecisely sized cartridges.

 

From : http://www.dcr.net/~stickmak/JOHT/joht18measure.htm

 

Volume standards are a little trickier, but have been found. Weight standards (artificial ones, as opposed to the natural ones mentioned above) are perhaps the most durable, and the easiest to produce with reasonable accuracy and precision. Scale weights are found in many archeological digs, and those from a particular region and era are surprisingly consistent.

 

Simple scales can be quite accurate and precise. I reload my own ammunition, a practice which requires high accuracy and precision over a wide range of weights. A few years ago I decided to have my powder scale calibrated at the local office of weights and measures. This scale was inexpensive, around $40, and made mostly of plastic and stamped sheet steel. Yet it was so accurate and precise that the metrologist who performed the calibration was impressed. When you consider that a difference of a tenth of a grain of powder (a grain being 1/7000th of a pound, or 0.0648 gram) can cause a change in bullet impact of over a centimeter at 100 meters, you can see that these scales must perform their function well.

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From : http://www.dcr.net/~stickmak/JOHT/joht18measure.htm

 

Volume standards are a little trickier, but have been found. Weight standards (artificial ones, as opposed to the natural ones mentioned above) are perhaps the most durable, and the easiest to produce with reasonable accuracy and precision. Scale weights are found in many archeological digs, and those from a particular region and era are surprisingly consistent.

 

Simple scales can be quite accurate and precise. I reload my own ammunition, a practice which requires high accuracy and precision over a wide range of weights. A few years ago I decided to have my powder scale calibrated at the local office of weights and measures. This scale was inexpensive, around $40, and made mostly of plastic and stamped sheet steel. Yet it was so accurate and precise that the metrologist who performed the calibration was impressed. When you consider that a difference of a tenth of a grain of powder (a grain being 1/7000th of a pound, or 0.0648 gram) can cause a change in bullet impact of over a centimeter at 100 meters, you can see that these scales must perform their function well.

And I'll bet that a comparable difference in overall length would result in an even greater change in impact, since it would result in a different case volume and pressure.

 

Consistency is so important, sometimes it's a wonder that we hit the targets at all. :unsure:

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And I'll bet that a comparable difference in overall length would result in an even greater change in impact, since it would result in a different case volume and pressure.

 

Consistency is so important, sometimes it's a wonder that we hit the targets at all. :unsure:

 

What is this "hit the target?"

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