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Old 07-12-2018, 10:57 AM   #71
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No apologies necessary Frank. I think most of us here, especially those of us that reload, pay attention to this type of data. We may not all comprehend the technical aspects of these formulas but I for one find it interesting and useful and your analogy to horsepower ratings was quite appropriate.

Thanks also to Drew for the reams of info he distributes over this forum.
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Old 07-12-2018, 11:04 AM   #72
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As a victim of a public education in the great State of Missouri K - post-graduate I'm not so good with numbers. I think we are all just trying to understand, despite we and the British speaking a different language

A not unreasonable summary, which Bro. Bruce has been telling us for years, is that there is no reason to believe turn-of-the-century Bulk (and esp. Dense) Smokeless Shotshell pressures were much different than today's loads.

The fluid steel and pattern welded barrels were not 4140 however, many are now 100 years old, and some were neglected or abused. I think we also understand our margin for error is less.
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Old 07-12-2018, 12:09 PM   #73
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It does appear that Coxe was simply converting tons X 2240 to derive psi.

From “Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics”, 1927, a DuPont Oval Pamphlet, p.20.
Dram Eq. is listed on the graph as 3; charge was 1 1/4 oz. Pressure is expressed in Long Tons.

Using Burrard’s estimated Tons Lead Crusher Pressure (Cp) conversion to PSI (pound force per square inch): (Cp x 1.5) - .5 = TSI; TSI X 2240 = PSI in BLACK
IF Coxe was simply converting Tons X 2240 to estimate the PSI in BLUE and is compatible with other 3 Dr. Eq. published measurements (+ 10-14% for modern transducer numbers)

Ballistite maximum pressure at 1” was 4.9 Long Tons = 15,344 psi (by Burrard) or 10,976 psi
Schultze at 1 3/4” was 4.5 Long Tons = 14,000 psi or 10,080
DuPont Bulk at 1 2/3” was 4.1 Long Tons = 12,656 psi or 9,184
FFFg at 1 1/2” was 3.8 Long Tons = 11,648 psi or 8,512
DuPont Oval at 2” was 3.5 Long Tons = 10,640 psi or 7,840

I wish he'd just used the Tarage table for psi instead
Or maybe he did, and for some unfortunate reason chose to express the numbers as Long Tons??

The BLUE psi numbers are similar to “Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics”, 1933. The pressure curves (PSI by LUP) are also for a 3 Dr. Eq. 1 1/4 oz. load (+ 10-14%)
DuPont MX = 9,800 psi
DuPont Bulk = 9,600 psi
FFFg = 9,000 psi
DuPont Oval = 8,700 psi

Last edited by Drew Hause; 07-12-2018 at 12:35 PM.
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