This is a custom revolver design. I combined various things from different .38 special revolvers to get to what you see here, although, I used a Rexio revolver as the main reference for the general shape and design.
Created with Far Cry 3 triangle count and texture resolution specifications in mind: 15k triangles and 2048x2048 pixels maximums. Textures are 2048x2048 and were created using Photoshop. Low poly model is about 11k triangles. All modeling was done in 3ds max and I used xNormal for baking maps.