Saad:
Here's a couple of references on Delcour-Dupont that I alluded to: http://damascus-barrels.com/Belgian_Trade_Marks.html

http://www.littlegun.be/arme%20belge/artisans%20identifies%20d/a%20delcour%20dupont%20gb.htm


"JA" would have been the mechanic that fitted the tubes to the action.

Kind Regards,

Raimey
rse