Thank you!!!!! I will show this post to my wife Barbara!!! What you say is very true after all to us Americans what is a pin? To the British it is a screw that you remove with a turn screw, and a tumbler is the hammer on a double.
Why there are so many French doubles up here in the Maine area I do not know other then our proximity to Canada but these guns should not be ignored and your point is well taken about the proofing of these guns. My Verney Carron is double proofed and if you check the book on proof marks you will find that it had the re-inforced proof which means a proof load of at least 20,000 psi or higher. On the other hand some French guns get proofed at lower pressure then max loads for modern ammo even though these guns are not vintage black powder jobs or so it seems from the proof marks. For example I have a 16 that was proofed at 850 kilos per cm which is on the low side and their is no indication as to weather it is bars or PSI. If you look at this action and anilise its strong point you would think it could take TNT for a proof load. This is the action I used for my .450 # 2 NE but I had other people who had mor knowledge then me about these things check it out first. Even so, and with any gun with major modifications you must re-proof the thing and not with you holding on to it!!!! In this case I used 118 grains of IMR 4831 with a 500 grain bullet as the blue pill. 118 grains of H 4831 powder is the A Square max load for a 465 grain slug, and the IMR is a few steps faster.
This much powder even with this bullet is very much on the HOT side so seating a 500 grain slug on top of that load was probably a bit intensive but a proof load should be around 30% over standerd so I gave it a shot. Two shoots from each barrel and nothing changed and 100 shots later with around 100 grains and a 480 grain bullet and still nothing has changed so all apears well.