Kilroy was kind enough to send me his original image. It was taken at ISO 200, using a 35mm lens, with a crop sensor body.
I went ahead and did an edit of it in Lightroom, and took a video of the process.
Basic steps involved having lightroom correct for known issues with Lens/Body combos (every camera has em'), and then tweak the white balance.. From there went through and started to clean up the white background, so that it was whiter/brighter, and to get rid of the cloth texture - at some point during the video you can see me turn the highlights red - this allows finding "dirty areas" that you want to clean up (the red is basically pure white). Around the gun itself, I desaturated the colors a bit, to get rid of the bluish cast from the gun onto the white background, and turn it into a grey. For the gun itself, I increased the sharpness and clarity, pulled some shadow, and added some black back into compensate for the shadow removal. Were I go further, I would tweak the shadows on the magazine an grenade further, desaturate the shadows around the gun a bit, and maybe add some accents to the brass.