Great stuff as usual! I was shocked to find out you are only 19 (like Sandyman, I always thought you were older). You should totally enter the Teen Challenges here on CA before you are too old (I know I know, shameless plug for TC, but people always seem to forget about it and there isn't that much participation usually).
On the latest illustration I think it looks cool, especially the gun design, but I am not entirely sure about the blue background. To be honest, it seems kind of out of place and looks as though you simply didn't want to draw in a background, so threw in a solid colour. Other than that I think the guy getting shot could use some more work. His proportions are a bit off (arm too long, upper legs different lengths), and he can use some hue and saturation variation in his skin tones as now they are a bit plastic and dead looking.
Keep up the studies! I wanna see you applying the things you are learning from those charcoals into your other stuff!