Circa 1900-05 Live Bird gun

[Drew Hause]

1 1/4 oz. with 3 1/2 Dr. Eq. was the standard Live Bird load in the U.S. 1895 - about 1900; and although Krupp, Siemens-Martin and Whitworth fluid steel barrels were available, certainly most guns were Damascus

Sporting Guns and Gunpowders, “Tests Of Strain On Breech Actions”, in Field, 1892
1 1/4 oz. 3 1/2 Dram Bulk Smokeless Pressures in 2 3/4” case
https://books.google.com/books?id=inQCAAAAYAAJ&pg=PA86
Long Tons/ sq. inch converted to PSI by Burrard’s formula

(Proof) with 6 1/4 Drams “Tower Proof” Black Powder and 1 2/3 oz. shot – 4.51 Tons = 14,034 psi
3 1/2 Drams Curtis & Harvey’s No. 4 T.S. Black Powder – 4.2 Tons = 12,992 psi
“Schultze” – 4.28 Tons = 13,260 psi
(In a 3” case, with additional wadding the pressure for “Schultze” was 4.93 = 15,445 psi )
“E.C.” – 4.92 Tons = 15,411 psi

Note the SAAMI 2 3/4" 12g Max. is 11,500 psi

and BTW 1 1/4 oz. 3 1/2 Dr. Eq. (1275 fps) in an 8# gun = 27 ft/lbs free recoil
1 1/8 oz. at 1200 fps in today's 10# trap guns = 16.2 ft/lbs

[Cold Spring]

Originally Posted by Drew Hause

1 1/4 oz. with 3 1/2 Dr. Eq. was the standard Live Bird load in the U.S. 1895 - about 1900; and although Krupp, Siemens-Martin and Whitworth fluid steel barrels were available, certainly most guns were Damascus

Sporting Guns and Gunpowders, “Tests Of Strain On Breech Actions”, in Field, 1892
1 1/4 oz. 3 1/2 Dram Bulk Smokeless Pressures in 2 3/4” case
https://books.google.com/books?id=inQCAAAAYAAJ&pg=PA86
Long Tons/ sq. inch converted to PSI by Burrard’s formula

(Proof) with 6 1/4 Drams “Tower Proof” Black Powder and 1 2/3 oz. shot – 4.51 Tons = 14,034 psi
3 1/2 Drams Curtis & Harvey’s No. 4 T.S. Black Powder – 4.2 Tons = 12,992 psi
“Schultze” – 4.28 Tons = 13,260 psi
(In a 3” case, with additional wadding the pressure for “Schultze” was 4.93 = 15,445 psi )
“E.C.” – 4.92 Tons = 15,411 psi

Note the SAAMI 2 3/4" 12g Max. is 11,500 psi

and BTW 1 1/4 oz. 3 1/2 Dr. Eq. (1275 fps) in an 8# gun = 27 ft/lbs free recoil
1 1/8 oz. at 1200 fps in today's 10# trap guns = 16.2 ft/lbs

Drew, not to get anything started here again but I read that you're using "Burrard's conversion" factor to come up with those psi numbers. Can you please elaborate how that conversion relates/applies to period American lead crusher pressures, and from there to modern transducer measurement? Thank you.

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

[Drew Hause]

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.