Movies...the classics!

I like the shot pretty well, BUT... a hard-boiled dick of the era would hold the gun one-handed. You never saw anyone shoot with two hands in movies back then, or much in real life for that matter. You'd have to figure out what to have him do with his left arm then, though.

And it wouldn't be a BB gun with a relatively long barrel, it'd be a snubby .38, or maybe a 1911 .45. (Realistic looking airsoft guns can be had for $30 or so.)

Also the position of the rear view mirror make it look like he's resting his arm on it. Moving just a few inches to his left would show a definite gap and eliminate the confusion.

There's a slight crease in the right side of his hat brim that throws a triangular shadow, that looks in the small pic like hair sticking out from under his hat.

I like that his face looks like its been smoothed a bit, as if he's wearing actor's makeup. (Although I might be seeing something that isn't there.) The lighting, overall composition and B&W tone look good