French proof marks

Evanguy

Evanguy

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I'm wondering if someone can tell me if this shotgun was nitro proofed and possibly roughly what date it was made

these are the only makings on the gun other then the serial number that appears on every part including the wood.


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"For barrels proof with semi-smokeless T powder"

Doubtful that "semi-smokeless T" powder was the same as modern nitrocellulose powders. It may have been an early version of smokeless powder that generated more (or less) pressure than current formulations. Regardless of the potential for misunderstanding, a shotgun from that era is almost guaranteed to have 2 1/2" chambers, not the modern minimum of 2 3/4 inch chambers. Note that 2 1/2" chambers are actually 2 3/4" long and 2 3/4" chambers are actually 3" long. This is to allow a 1/4 inch for the crimp to open into without obstructing the forcing cone.

All this is to say, no matter if you've measured the chambers to be 2 3/4", and no matter if the proofs are for "semi-smokeless T" powders, the gun should only be used with 2 1/2 inch LOW PRESSURE or BLACK POWDER shells. If you choose to use modern nitrocellulose (smokeless) in 2 3/4", nobody on this site can be held responsible for the damage to your gun, your face, or your hands.

Also, none of the above speaks to the catastrophic failure or long term excessive wear that people using nitro shells inflict on vintage guns.

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straightshooter said:
"For barrels proof with semi-smokeless T powder"

Doubtful that "semi-smokeless T" powder was the same as modern nitrocellulose powders. It may have been an early version of smokeless powder that generated more (or less) pressure than current formulations. Regardless of the potential for misunderstanding, a shotgun from that era is almost guaranteed to have 2 1/2" chambers, not the modern minimum of 2 3/4 inch chambers. Note that 2 1/2" chambers are actually 2 3/4" long and 2 3/4" chambers are actually 3" long. This is to allow a 1/4 inch for the crimp to open into without obstructing the forcing cone.

All this is to say, no matter if you've measured the chambers to be 2 3/4", and no matter if the proofs are for "semi-smokeless T" powders, the gun should only be used with 2 1/2 inch LOW PRESSURE or BLACK POWDER shells. If you choose to use modern nitrocellulose (smokeless) in 2 3/4", nobody on this site can be held responsible for the damage to your gun, your face, or your hands.

Also, none of the above speaks to the catastrophic failure or long term excessive wear that people using nitro shells inflict on vintage guns.

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Straightshooter is correct, semi-smokeless is not the same as smokeless. The "PM" is for "poudre pyroxylée M," which was developed by the French in response to the wood-based semi-smokeless powder invented by the Prussian artillery officer, Captain Johann Edward Schultze, in 1860. It was semi-smokeless, as it was partly composed of black powder. It would not produce pressures like the nitro powders of today. Powders "T", "J" and "S" came later, and had different compositions and proportions.

If anyone is interested in the convoluted early history of smokeless powders and its use well before guns were proofed for them (!), may I suggest the following read:
https://www.vintageguns.co.uk/magazine/gun-cotton-and-pinfires
 
Thanks guys. Ok I'll skip the modern ammo for it. And thanks for the note about it being 2.5"

I'm going to buy some all brass hulls and load them ffg blackpowder.

I hope I can find a h777 load for it, if not I can use real blackpowder, I have 5 pounds of h777 is why I want to look for an h777 load
 
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