Excellent piece! Can't wait to see the final image.
I worked with Gatling guns for several years and I feel that if you put some more detail into those two feed belts, the extra work will really pay off. One idea is to color the tips of the rounds...maybe every 10th or 12th projectile... to indicate a 'special' projectile (tracer, incendiary, etc).
Nice. Improved detail, more refined lens flair. Also, thanks for keeping it the same size etc, makes comparisons easier.
Only thing I liked better in the old version is the belt section right before it goes into the box in the top-left (not the bit arcing over head, the one coming down), it almost looks like it's moving the wrong way in this version.
panel lines are real fun if you get the feel for them! look at cars, jets, design products! a great reference for panel lines. see them as additional detail with which you can spice up a "boring" big surface