Another 30 minutes work in Blender
Hi there. I'm a big Blender user, and I see some things in this image that really *need* to be addressed. Fortunately, I can give you explicit instructions on how to fix them.
First, and most important, you need to "Set Smooth" all of your objects. I can see the polygons in the barrel, the handle, and the chamber. If you are willing to learn about Edge Weight (using the "Shift-E" command), then maybe you could even try "Add Modifier" in the Mesh Tools and choose "SubSurf". I also noticed that many edges are beveled, but not all (like the hammer). You should bevel everything to give it a more realistic look; it's a lot of work, but worth the effort.
The lighting and depth of field blur are excellent, and so is the wood of the handle. You made really good use of the built-in "Wood" texture there. Also, nice choice on the image for the floor's texture.
Finally, your materials. The floor: turn down the reflectivity and up the specularity on the wood floor. It will reflect just the brightest lights in a very vague and blurry way, like a real polished wood floor. Also, in Materials on the Textures "Map To" panel, you might want to click on "Nor" to make the wood bumpy according to the image texture. If you don't like that Normal Map, then try others (I personally like the built-in Clouds texture with NoiseSize = 0.050). The gun metal: again, too reflective. Turn it down, and maybe play with the Fresnel setting; the metal isn't a pure mirror, it'll actually "gray down" the reflection (like how a red Xmas ornament reflects the room in a red hue). Also, you could add a background image (go to Shading panel, then click the World button and assign a texture like usual) that the gun metal would reflect, adding an extra bit of realism.
On the whole, this is an EXCELLENT first go, and Blender is not an easy program to master. Best of luck, and I look forward to seeing your future stuff, especially considering the high quality of your illustrated works. Cheers!