IEM Cologne is now over 😠- However you can still purchase a Viewer Pass and get the Bronze Coin, plus create souvenirs up until Get your Viewer Pass & Bronze Coin
Choose a full colour image to apply as a paint which lines up 1:1 with the weapon's UV map. This finish wears directly to the substrate.
You can do Durability & Masking via the alpha channel.
You can also use a bump map.