I don't say this often because I'm not a jealous person but I'm extremely envious of your drawing abilities. I don't just say this because "Oh, the shading is amazing" or "the background is awesome". I say it because of the improvement you constantly make. Don't get me wrong, I still love your new stuff but I'm just fascinated to see that (what, 5 years ago?) you were already doing nearly professional-grade work. Now, back to my point: yes, I am envious of your skill (quit being so talented!) but I am even more envious of how quickly you improve on something that's already very well done.
I love how you drew this. It looks real, since you got most of the shading and lighting right.
The folds in the clothing are well done too.
The details are pretty amazing and he expression on his face was well done too!
The only thing is that I feel like you drew the finger on the trigger just a little too long. Unless that's just me being blind again. (Which is probably the case. FFF.) So really, the only thing I'd say you would need to fix about this drawing are the fingers. Besides that, it's an awesome piece of work!