I know this is not genuine Damascus, but Per Billgren of Damasteel AB in Sweden now has a new alloy that can be browned like traditional Damascus and which is suitable for modern firearms - barrels, parts etc as he says on this link. To copy and paste from there:

2x .y Low Alloy Tough Hardening Damascus Steel
Applications:

Hunting firearm barrels and parts for browning or blueing. Knife blades. Axes and other edge tools. Damascus forging including forge welding.
Properties:

Hardenable up to 55 HRC. Excellent toughness. Excellent forgeability and forge weldability. No corrosion resistance.

Just a suggestion as you gentlemen are planning a massterpiece.