Hey there. Sorry for the long wait time, due some family issues I've had to put aside my computer for a while. In response to your question, I'm afraid that I am unable to allow my work to be used for free, and according to your profile page you are unable to pay. If you'd be interested in commissioning me, I'd be more than happy to allow this or any other concept of mine to be used, and would also be willing to generate content or provide firearms expertise specifically for you, but I do have to uniformly charge for my services, or I would be unable to charge at all. My apologies.
Well, that depends on what it is you need, exactly. I can do anything from plain old 2D to multi-view orthographic drawings with full writeups, black and white to colored, flat to textured. 2D black and white lineart with no consultation or writeup to speak of is cheaper, but other levels offer more realism and detail for your universe, game environment, and fully colored and textured drawings can be used in game manuals. I personally pride myself on realism and attention to detail when it comes to mechanisms, calibers and capabilities, and I enjoy seeing games with good research behind them, but not all gamers are quite as concerned with that as I am.