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Brittany Man, DAM16SXS, dogon, Drew Hause, K Crowley, liverwort, Stanton Hillis, Ted Schefelbein
Total Likes: 10
Original Post (Thread Starter)
by Drew Hause
Drew Hause
We are fortunate today to have an abundance of turn-of-the-century pressure data, which can be found here

I stumbled upon another interesting source; “Shotgun Ballistics”, Charles Askins, Outdoor Life, July 1917

Pressure X 2240 converted to PSI (not Burrard's formula and I am confident that is how DuPont did it), which requires adding 10-14% for modern piezo transducer numbers.

Note modern SAAMI standards allow +/- 90 FPS and +/- 900 PSI = .4 Long Tons

12g 2 3/4” 1 1/8 oz.
……...…………...3 Dram…..3 1/4…..3 1/2…..3 3/4…....4
DuPont Bulk…...7,750……7,840….8,019…..9,744….10,640 PSI
“Schultz” Bulk…8,064……8,960….9,520…..9,878….9,744 PSI

[Linked Image from photos.smugmug.com]

16g 2 7/8” 1 oz.
………...……….2 1/2 Dram…..2 3/4…....3…....….3 1/8..…..3 1/4
DuPont Bulk….7,683…….....8,243..…9,223......9,811…..10,080 PSI
“Schultze”…….8,333…………9,677..…10,461..…12,790..…11,200 PSI

[Linked Image from photos.smugmug.com]

20g 2 7/8” 7/8 oz.
………….…...…..2 1/4 Dram…2 1/2…....2 3/4…..3
DuPont Bulk……10,685…..…12,208..…12,902…14,538 PSI
“Schultze”………11,715...…12,499…..12,858…13,530 PSI

Note the maximum pressure observed for the standard 7/8 oz. 2 1/2 Dram “Schultze” load was 13,978 PSI + 10-14% is approaching proof load pressure at > 15,500 PSI
Liked Replies
by ellenbr
Now if we could only get current shotshell companies to cough up their pressures?


2 members like this
by Ted Schefelbein
Ted Schefelbein
Pretty sure anything B&P is a CIP load, Stan. Anything CIP is going to be more consistent on pressure, and OK to use in any gun that remains in proof, even twist or Damascus. SAAMI, not so much. It will be at or under SAAMI max. That is about all you will know. That is by design, by the way. It give the manufacturers great leeway in how and what they use to load ammunition.

I agree with your number for old guns, but, I suspect that getting that number, consistently, with factory loaded ammunition that makes no claim to being anything but SAAMI compliant is a tough thing to do. The boutique ammo guys can and do make it. But, expecting to get it off a shelf at the local mart from run to run is perhaps a bridge too far, even with testing a few from time to time.

My oldest gun has steel barrels with .060 wall, 9” from the breech. I was always suspect of thin walls, but, it was more of a worry of denting them, for me. Somebody right here posted the results of testing on about half a dozen, older, 20 gauge factory promo loads that were right up against SAAMI max a few seasons past. That, was sobering to me, and, changed how I think about old doubles and ammunition. Pressure is the bugaboo.

Be well, Stan.

2 members like this
by Drew Hause
Drew Hause
The 1928 edition of “Smokeless Shotgun Powders” by Wallace Coxe, ballistic engineer of the Burnside Laboratory of the E.I. du Pont de Nemours & Co. reported 3 1/2 Dram Eq. 1 1/4 oz. loads:
NOTE: pressures were measured by crushers (LUP) and modern transducer measurement pressures would be 10 – 14% higher
DuPont Bulk smokeless powder - 11,700 psi
Schultze Bulk smokeless powder - 11,800 psi
28 grains of Ballistite Dense smokeless powder - 12,600 psi
(Note all 3 are greater than the SAAMI 12g 2 3/4” recommended maximum pressure of 11,500 psi)
40 grains of DuPont Oval Progressive Burning powder used in the Super-X loads - 9,400 psi

There is a Hunter Arms Co. Pressure Curve dated June 10, 1929, from the McCracken Research Library, Buffalo Bill Center of the West (found by Gary Rennles) very likely from DuPont
12g 3” ‘Record’ 1 3/8 oz. shot presumed 1275 – 1295 fps = 13,250 psi
12g 2 3/4” Super-X ‘Field’ 1 1/4 oz. shot presumed 1330 fps = 10,750 psi
12g 2 3/4” 1 1/4 oz. 28 gr. (Dense) Ballistite = 12,900 psi
12g 2 3/4” 1 1/4 oz. 3 1/2 Drams DuPont Bulk = 10,000 psi
+ 10-14%
1 member likes this
by Ted Schefelbein
Ted Schefelbein
Originally Posted by ellenbr
Now if we could only get current shotshell companies to cough up their pressures?



I suspect they prefer to be vague about pressure to allow for lot to lot variances in pressure, all the way up to SAAMI maximum. The only guys who care about pressure, are us, and we won’t be around forever.

1 member likes this
by Paul Harm
Paul Harm
Ted, that barrel looks like something was lodged in the bore, not high pressure. High pressure loads have the chamber opened up, not the bore. Now, if the reason for your post was to show a gun with very thin walls, that's a little different. But then who in their right mind would shoot a gun with .018 barrel wall thickness 9" from the breech ? That's not a over pressure question, but one of sanity.
1 member likes this
by FallCreekFan
Thanks, Doc.
1 member likes this

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