A Colt Walker. The model design was based on the one from the Create: Love & War mod for Minecraft, but was rebuilt from scratch to match the proportions of the real-life Colt Walker revolver. It also uses custom textures made using Blender's built-in texture painting system in combination with GIMP for additional editing. And I was surprised that I managed to make a good texture, considering that I never made a texture completely from scratch. But I think it's also because I have tons of reference images, which allows me to better design the textures.