Wire inlays are not difficult to do, but they are time consuming.
I start off by transferring the pattern onto the gun stock and figuring out where I want it. Then remove the stock and begin cutting the lines.
Each "wire" is more like a flat ribbon that gets driven into the wood with a small tack hammer.
The larger inlays are cut by hand using a jeweler's saw and jig. After the inlays are hammered in, the entire stock is sanded to a fine grit, and a finish sealer is applied.
Here's the opposite side of the stock.
Other examples of wire stock inlay available on custom guns at Coastal Defense.