That picture is bizarre. The gun itself appears to be well maintained, but the mount is corroding and that ammo should have gone over the side, not into the gun. It must be the perspective that makes the rounds look so big, but no lense made them look that ugly. I always figured squids didn't know anything about guns, but I was mistaken.
They don't know anything about ammo.
Maintenance on the gun is likely performed in a seperate armory or maintenance bay set up for the job, by someone who really knows what they're doing.
And if the ammo looks like it's on its last legs, yeah, I'd relink it if I had new ones available, but as most of the experienced .50 gunners here have noted, John Browning's jackhammer will likely run okay even with it in that condition: it was designed to function in the aftermath of the trench warfare conditions of the Great War, and numerous real improvements in material and feed devices have been made since then. And, of course, it only has to work once.
Personally, I'm sort of gratified to find that the old stuff has been hauled out of the bunkers and put aboard ship where it can be used if needed- and that the recent production .50 ammo is going to the grunts in Iraq and Afghanistan.