doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com French Powder Strength & Proof Pressures

Thank you again Wolfgang!

https://en.calameo.com/read/0054478584946e91a2418







J2 is listed for 12g as 3.5 gram = 54 grains = 3.42 Dr. Eq. but with 1 1/8 oz.
J1 for 10g & 8g
T for 12g is 2.2 grams = 34 grains = 3 Dr. Eq. with 1 1/8 oz. (I think the 11.5 grains/dram conversion is correct)

https://books.google.com/books?id=_IVMAAAAYAAJ&pg=PA933&lpg lists Poudre T 2.5 gram = 38.6 grains = 3 1/3 Dr. Eq. with pressure 600 kg/cm2 = 8,534 psi + 10 - 14% but does not specify oz.
The other "33 grain" powders 1 1/8 oz. 3 Dr. Eq. pressures were about 9,500 psi + 10 - 14%

Standard 12g Proof with Poudre T was 3.46 gram = 53.4 grains = (about) 4 2/3 Dr. Eq with 35 grams = 1 1/4 oz. shot
Superior Proof with Poudre T was 4 gram = 61.73 grains = (about) 5 1/3 Dr. Eq with 38 grams = 1 1/3 oz. shot

p. 46 and at the bottom it states Superior Proof with 4 grams Poudre T with 38 grams shot generates pressure of 1208 kg/cm2 = 17,182 psi + 10 - 14%




Post-1923 a Crowned PT indicated proof at 850 Kg/cm2 = 12,090 psi and (Superior Proof) 2 Crowns at 11,000 Kg/cm2 = 15,646 psi + 10 - 14%

From https://www.shotguns.se/html/france.html

Treble Preliminary Proof is 18,490 psi = 1300 Kg/mm2



1928 Manufrance Ideal PRESSION 1100 KILOS with quintuple preliminary proof

Superior Poudre T Proof is with 3 shots

I thought I'd post the image that Hermano Juan Carlos found in the 1901 Verney-Carron catalog in case it was lost from the image hosting site.
It, and the 1900 Manufacture Française d'Armes de St Etienne catalog would confirm that there was a Poudre R, which was discontinued prior to the 1914 Verney-Carron catalog.
After 1914, only Poudre T was used by the proof house for Nitro proof.
And the image confirms that only Poudre T was smokeless; the others were considered semi-smokeless.

The French equivalent to Nitro Powder is "Poudre Pyroxylée"



BTW: The (same) gunner in the first 4 images has a fairly upright head position; the 5th is crawling the stock and looks to have his thumb touching his nose

Shells offered in the 1939 Verney-Carron catalog
https://www.verney-carron.com/pdf/catalogue-1939-FR-Verney-Carron.pdf



With Poudre T and Poudre K2, but Poudre M was still available for purchase on p. 52
Poudre K2 was introduced in 1937 with lower pressures
T for 12g is 2.2 grams = 34 grains = 3 Dr. Eq. with 1 1/8 oz. is 7,170 psi + 10 - 14%
K at the same load is 6116 psi + 10 - 14%
Possibly K2 was a Progressive Burning powder like DuPont Oval?

This discusses ballistic testing of the shotshells by the Proof House



Lowest 500 Kg/mm2 = 7,112 psi (the 3 Dram 1 1/8 oz. Poudre T load above) + 10 - 14%
(The origin of the oft repeated 8000 psi guide for vintage shotguns??)
Highest 620 Kg/mm2 = 8,818 psi + 10 - 14%