Looks great. I really like the finish and weathering. Just a few tips:
1. Place some diamond-pattern mesh on the bottom of the rear turret bustle rack (or use a PE add on part from Voyager/Eduard/Tamiya). You may be using the Dragon M1A2, which doesn't come with the mesh (but should).
2. Paint the two 7.62 ammo cans in the side bustle racks (each one is just to the rear of the smoke grenade launchers) in dark olive drab--they should not be sand colored.
3. The commander's .50 cal is missing its ammo can and the can holder. Make sure to add them.
4. On the M1A2 the commander's cupola does not turn with the .50 cal (the weapon rotates around the cupola using its own ring), so the hatch and periscopes will always be in the same position even if the weapon is slewed to the side. Pointing the cupola straight forward is the easiest solution, although you could do some styrene surgery to move the weapon mount to the side.
Hope this helps!