Gene,
In the case of the French gun, I think you will be fine. It’s hard to find a French double with thin walls. Pretty decent steel by that era, as well. I tell people you will quit before the gun does, they are usually very light, with high levels of proof.

The Damascus gun, well, I don’t know. Some of the Federal promo loads are loaded with pretty cheap powder, be nice to have a grasp of pressure instead of velocity, as the two aren’t always on the same plane, so to speak.

Best,
Ted