c.u.p vs psi.

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c.u.p vs psi.

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06 June 2001, 05:53

<jim k>

c.u.p vs psi.

What is the preasure difference between c.u.p. and psi. TNX
Jim

06 June 2001, 06:30

<bobshawn>

jim k __

CUP values vary sufficiently above, at, or below the more accurate PSI values that there is no honest mathematical method of comparison. When the occasion demands, like for a structural analysis of a firearm, I simply multiply CUP numbers by 1.17 to get me reasonably closer to a PSI number. The result is conservatively higher than the probable real value. I'm not advocating this method. It's still a "more than likely" guess.

Good shooting.

Robert

06 June 2001, 07:27

<jim k>

Tnx Robert.
Jim

11 June 2001, 12:26

<PowderBurns>

CUP relies on crushing a copper pellet in a specially made barrel setup. While the pellet is as uniform as possible, copper doesn't crush in a "straight line" (on a graph). Accordingly, higher CUP pressures cause the copper pellet to compress more tightly and reading precise variations in this compression become more and more exacting.

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