No offense, but it's... crude. Like something a 1st-grader would draw.
More detail, more refined lines, either of those would be good. Perhaps some shading. And the handle was a bit too large.
If I had my tablet with me, or a mouse, I'd try my hand at drawing a gun, but sadly, neither of those, and trackballs aren't exactly the greatest thing ever for drawing...
Well, if I wanted, I could use my tablet, but for some reason it's responding relatively; normally, if I place the stylus 1/4 down from the top, 2/3 from the right, then it would place my cursor 1/4 down and 2/3 from the right of my screen, if I dragged it down halfway, the cursor would move down halfway, but now, it stays in place no matter where I place the stylus, and the rate at which the cursor moves multiplies when the motion of the stylus only adds. As in, say I move the stylus at a speed of W. Then the mouse will move at X. W=X. Now let's say I move the stylus twice as fast, 2W. The cursor would move at 4X. So, W=X, 2W=4X. Not exactly 2x=4x, but you get the idea.