![]() |
Visit Drew Hause's homepage! | | |||||||||||||||||||||||||||||||||||||||||
|
|
#3 | |||||||
|
Quote:
Interesting that Askins wrote extensively in 1929 about American shotshell loading and pressure testing and although I read his volume many times I don't remember seeing any reference to Burrard nor anything other than lead crusher pressure in tons per sq inch. Let's take just one number from his chart for maximum loads of DuPont's Bulk smokeless as provided by its Brandywine Lab, i.e., 12-gauge 1-1/4 ounce and 3-1/2 drams shows an average of 4.70 tons. Now, correlating with the data here in the quote that would be about 14,750 psi. That doesn't make sense to me |
|||||||
|
|
|
|||||||
|
|
#4 | ||||||
|
Yes, those numbers are Burrard's conversion.
The long explanation starts just past 1/2 way down here Frank https://docs.google.com/document/d/1...UOZEFU/preview Here's the short version for us non-deep thinkin' types ![]() Burrard's conversion formula for Tons/sq. inch as measured by LUP is probably close to modern piezo transducer measured Pounds/sq. inch (PSI). Since we cannot KNOW the conversion for PSI as measured by LUP to PSI as measured by transducers, adding 10 - 14% to the load pressures reported as PSI by LUP seems reasonable. In a 1927 Western Cartridge Co. flyer “Super-X The Long Range Load” by Capt. Chas. Askins the 12g “Duck Load” (not specified but presumed to be 1 1/4 oz. Super-X “Field”) is described as 3 1/2 dram (38.5 gr. Powder; also not specified but no doubt DuPont Oval) at 1400 fps (at the muzzle rather than 3 feet) and 1000 fps at 40 yards, with a breech pressure of 3 3/4 tons or about 11,480 psi by Burrard’s conversion. All of Coxe's pressure curves are in the doc also.
__________________
http://sites.google.com/a/damascuskn...e.com/www/home |
||||||
|
|
|
||||||
| The Following User Says Thank You to Drew Hause For Your Post: |
![]() |
| Thread Tools | |
| Display Modes | |
|
|