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#3 | ||||||
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We now have excellent data as to the pressures generated by the turn-of-the-century loads that were recommended by Parker Bros. and the other double gun makers
https://docs.google.com/document/d/1...UOZEFU/preview Scroll down about 1/3 for Parker's proof testing protocol A DuPont Ballistic Table was published in Parker Brothers' “The Small Bore Shotgun” c. 1920 http://parkerguns.org/pages/PDF%20Do...%20Shotgun.pdf It is clear that this table converts Long Tons to PSI simply by multiplying by 2240; NOT using Burrard’s conversion Numbers require adding 10 - 14% for modern piezo transducer pressures. 12 gauge 3 Dr. Eq. 1 1/8 oz. = 8,110 psi 3 1/4 Dr. Eq. 1 1/8 oz. = 8,960 psi 3 1/2 Dr. Eq. 1 1/4 oz. = 9,900 psi 16 gauge 2 3/4 Dr. Eq. 7/8 oz. = 7,035 psi 3 Dr. Eq. 1 oz. = 8,980 psi 20 gauge 2 1/2 Dr. Eq. 7/8 oz. = 12,655 psi Pretty easy to match those numbers with factory loads today...NOT that 1 1/4 oz. 3 1/2 Dr.Eq. would be a good idea for 100 year old wood. We also know from published pressure-distance curves that the pressure with modern 1 1/8 oz 1200 fps loads after 18" is < 500 psi OTOH I am increasingly convinced that there are VERY few vintage doubles with unmolested barrels and that "should be safe with light loads" is very dangerous advice
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http://sites.google.com/a/damascuskn...e.com/www/home |
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| The Following 8 Users Say Thank You to Drew Hause For Your Post: |
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#4 | ||||||
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Barrels , but I tend to not get overly intrested about guns that were made BEFORE they started making a radius cut between the breechface and water table . Plenty people shoot the earlier ones with squared corner , I just prefer radiused .
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Parker’s , 6.5mm’s , Mannlicher Schoenauer’s and my family in the Philippines ! |
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