shotgun proof marks

All.

I would greatly appreciate some assistance on deciphering some of the marks in my shotgun. It is Belgian or French. My father gave it to me and I want to use it occasionally on the skeet range. It looks as though it has had damage to the barrel repaired in the past with another cartouche and number stamped on the repaired barrel. See photographs. Here is what I think the symbols are. I would appreciate it if any of you could provide any additional information. Have been unable to attach photos but can send them separately.

Crown with PT underneath: French Definitive Nitro Proof? What pressure is this?
Standing Lion?
#s 65 and 182 on both barrels?
Cartouche AXF inside an oval on both barrels?
Cartouche on repaired barrel barely legible some sort of coat of arms with the number 596 underneath?

I have fired the gun with no problems. The only ammunition it will easily chamber due to the very shallow lip around the chambers is Gamebore. The flange or base around the lip of Gamebore is tapered so it seats nicely. The ammo is 2 ?" and develops max pressures of 3 tons psi or 850kg per cm2 which I think is ok. Would greatly appreciate any advice or information on the above marks.

Thanks, Tom