Those hoods are standard issue (at least they were back in the 1990’s) for anyone on damage control or gunnery duties. They are made of a flame-retardant material to prevent flash burns. It is curious that the gunner is wearing one, but no gloves, and his mate is wearing a different type of hood, more like what I am familiar with.
I think that the orientation of the links suggest that the TP rounds are first in line to be fired. It’s been a long time since I saw a Bushmaster loaded, but I recall the links being “on top” of the cartridges when loaded. I do not know if the naval version has dual feed, but the Bushmaster I am familiar with could be fed (and was) from both sides, so the belt on the left could be set up for TP rounds first, left side feed, or TP rounds last for right side feed, or just the opposite depending on which side the belt is loaded into!