the vest looks a little light in shade to the pictures of him, any way to darken it?
and the revolver looks a little too organic,
what did you use to build up the shape? heated up styrene? wonderflex? craft foam?
i like what you were going for, but i think theres too many inconsistent lines and it looks "soft" in areas, you have laired your white "building material" to overlap in places, or like at the back of the revolver chamber, over existing detail, which results in it having a slightly melted look.
while that effect may be good for some props. a weapon is something you want flat surfaces on, even if the surface is curving, which is fine, like around a pipe, you don't want it to be an uneven surface.
harder plastics like sheet styrene are great for this, because you can always sand out the areas that aren't 'flat' or smooth.
your attention to detail is looking good, perhaps the trigger guard could do with extending and bulking out a little, but i think your main problem is your choice of materials, and a bad choice in materials is something that's hard to work around.