Proof Testing in the U.S. - 10/01/20 11:00 PM
Finally stumbled upon a report from 1894 regarding proof testing in the U.S., and thought I summarize what we have documented.
"Schultze" was one of the first smokeless powders, developed in 1862, and was first marketed in the U.S. by Von Lengerke & Detmold in 1887.
The American "E.C." & "Schultze" Powder Company was established in Oakland, New Jersey in 1890, and was purchased by DuPont in 1903. DuPont Bulk Smokeless was introduced that year.
Forest & Stream, November 24, 1894
"Gas Pressure or Bursting Strain"
https://books.google.com/books?id=19kwAQAAMAAJ&pg=PA459&lpg
The proof-house charge of the American Testing Institution for a 12-bore gun develops a gas pressure of over 18,000 lbs. to the square inch. It is the same strain to which finished guns are put abroad. No gun would stand such a strain for any length of time. About 10,000 lbs. may be considered of touching the safety limit, and for some guns even is hazardous. A load giving about 8,000 lbs. pressure and less is better suited for the average gun and everyday use.
(The pressures were no doubt measured using LUP and modern transducer values would be 10-14% higher.)
Maybe this is where the frequently expressed 8000 psi load recommendation came from?!?
April 20, 1895 Sporting Life
"Shall Guns Be Tested?"
https://digital.la84.org/digital/collection/p17103coll17/id/48142
July 27, 1895 Sporting Life
Call for Government Proof House for Nitro Powder Testing
https://digital.la84.org/digital/collection/p17103coll17/id/48122
A.H. Fox 1911 Catalog
"Fox Proof Test means that every gun is tested with enormous over-charge according to the requirements of European governments."
(Under the 1896 British Rules of Proof, if 6 1/2 Drams Curtis and Harvey's "T.S." [Treble Strong] No. 2 and 1 2/3 oz. soft No. 6 shot was used for Definitive Proof, the pressure generated was 16,400 psi; if 90 grains = 6 1/2 Dram "E.C. No. 1" Bulk Smokeless Powder, 16,100 psi + 10 - 14% for either.)
From "Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics" by Wallace H Coxe; E.I. du Pont de Nemours & Co., 1927, p. 54
"It is generally conceded that a definitive proof should develop a pressure 25 to 40% greater than the service pressure to which it is expected the gun will be subjected."
LTC Calvin Goddard writing in "Army Ordnance" in 1934, stated that Hunter Arms proof tested 12g 2 3/4" chamber barrels at 14,300 psi + 10 - 14%.
A Parker Service and Proof Load table was published in the 1930s and reproduced in the The Parker Story p. 515. 12g 2 3/4" shell Service Pressure is 10,500 psi. Definitive proof used 7.53 Drams Black Powder and 2 oz. shot with a pressure of 15,900 psi + 10-14%, or more than 17,500 psi.
LTC Calvin Goddard reported the same numbers in "Army Ordnance", 1934. He wrote that Parker followed the SAAMI standards of that period: 13,700 psi proof, 9500 psi service for 2 5/8" chamber; 15,900 psi proof, 10,500 psi service for 2 3/4" chamber (by LUP) + 10-14%
Ithaca advertisements stated that barrels were proved with a "double charge of powder and 1 1/2 times the normal shot load"; or (possibly) 6 1/2 Drams Black Powder with 2 1/4 oz. of shot if the standard load was 1 1/8 oz. shot and 3 1/4 Dram Eq.
Jack O'Connor wrote in Outdoor Life in 1942 that Lew Smith, President of Ithaca Gun Co. stated the Proof Loads were 17,500 psi + 10 - 14%
The Winchester Model 21 introduced in 1931 was proved with a "Violent Proof" (VP) load reported to be 7 1/2 (long) tons = about 24,000 psi by Burrard's conversion.
Modern 12g and 16g 2 3/4" and 3" SAAMI Recommended Proof Pressures
http://saami.org/specifications_and...download/Z299-2_ANSI-SAAMI_Shotshell.pdf
If a manufacturer uses a SAAMI proof loads, then the gun will be proofed by a lot of no less than 10 shots of ammo loaded to a maximum proof pressure of 20,500 psi +/- 900 + 4600 psi, or uber max of 25,100 PSI; and, will be similarly a MINIMUM average proof pressure of 19,000 PSI +/- 900 - 4600 psi for an absolute minimum proof of 14,400 PSI.
"Definitive Proof Cartridges should be loaded with the heaviest shot charge used at the time of introduction and the slowest powder which will meet the pressure values indicated for that particular shotshell to maintain effective pressure-distance relationship."
The powders used in proof loads are not specified on the SAMMI site.
"Schultze" was one of the first smokeless powders, developed in 1862, and was first marketed in the U.S. by Von Lengerke & Detmold in 1887.
The American "E.C." & "Schultze" Powder Company was established in Oakland, New Jersey in 1890, and was purchased by DuPont in 1903. DuPont Bulk Smokeless was introduced that year.
Forest & Stream, November 24, 1894
"Gas Pressure or Bursting Strain"
https:/
The proof-house charge of the American Testing Institution for a 12-bore gun develops a gas pressure of over 18,000 lbs. to the square inch. It is the same strain to which finished guns are put abroad. No gun would stand such a strain for any length of time. About 10,000 lbs. may be considered of touching the safety limit, and for some guns even is hazardous. A load giving about 8,000 lbs. pressure and less is better suited for the average gun and everyday use.
(The pressures were no doubt measured using LUP and modern transducer values would be 10-14% higher.)
Maybe this is where the frequently expressed 8000 psi load recommendation came from?!?
April 20, 1895 Sporting Life
"Shall Guns Be Tested?"
https:/
July 27, 1895 Sporting Life
Call for Government Proof House for Nitro Powder Testing
https:/
A.H. Fox 1911 Catalog
"Fox Proof Test means that every gun is tested with enormous over-charge according to the requirements of European governments."
(Under the 1896 British Rules of Proof, if 6 1/2 Drams Curtis and Harvey's "T.S." [Treble Strong] No. 2 and 1 2/3 oz. soft No. 6 shot was used for Definitive Proof, the pressure generated was 16,400 psi; if 90 grains = 6 1/2 Dram "E.C. No. 1" Bulk Smokeless Powder, 16,100 psi + 10 - 14% for either.)
From "Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics" by Wallace H Coxe; E.I. du Pont de Nemours & Co., 1927, p. 54
"It is generally conceded that a definitive proof should develop a pressure 25 to 40% greater than the service pressure to which it is expected the gun will be subjected."
LTC Calvin Goddard writing in "Army Ordnance" in 1934, stated that Hunter Arms proof tested 12g 2 3/4" chamber barrels at 14,300 psi + 10 - 14%.
A Parker Service and Proof Load table was published in the 1930s and reproduced in the The Parker Story p. 515. 12g 2 3/4" shell Service Pressure is 10,500 psi. Definitive proof used 7.53 Drams Black Powder and 2 oz. shot with a pressure of 15,900 psi + 10-14%, or more than 17,500 psi.
LTC Calvin Goddard reported the same numbers in "Army Ordnance", 1934. He wrote that Parker followed the SAAMI standards of that period: 13,700 psi proof, 9500 psi service for 2 5/8" chamber; 15,900 psi proof, 10,500 psi service for 2 3/4" chamber (by LUP) + 10-14%
Ithaca advertisements stated that barrels were proved with a "double charge of powder and 1 1/2 times the normal shot load"; or (possibly) 6 1/2 Drams Black Powder with 2 1/4 oz. of shot if the standard load was 1 1/8 oz. shot and 3 1/4 Dram Eq.
Jack O'Connor wrote in Outdoor Life in 1942 that Lew Smith, President of Ithaca Gun Co. stated the Proof Loads were 17,500 psi + 10 - 14%
The Winchester Model 21 introduced in 1931 was proved with a "Violent Proof" (VP) load reported to be 7 1/2 (long) tons = about 24,000 psi by Burrard's conversion.
Modern 12g and 16g 2 3/4" and 3" SAAMI Recommended Proof Pressures
http://saami.org/specifications_and...
If a manufacturer uses a SAAMI proof loads, then the gun will be proofed by a lot of no less than 10 shots of ammo loaded to a maximum proof pressure of 20,500 psi +/- 900 + 4600 psi, or uber max of 25,100 PSI; and, will be similarly a MINIMUM average proof pressure of 19,000 PSI +/- 900 - 4600 psi for an absolute minimum proof of 14,400 PSI.
"Definitive Proof Cartridges should be loaded with the heaviest shot charge used at the time of introduction and the slowest powder which will meet the pressure values indicated for that particular shotshell to maintain effective pressure-distance relationship."
The powders used in proof loads are not specified on the SAMMI site.