Sailors clean the MK-45 5-inch/.54-caliber lightweight gun
Er. Misplaced decimal point? A 5-inch, .54-caliber gun would be a large-bore pistol with a 5" long barrel. What they're cleaning appears to be more of an artillery piece with a 5"×54 = 270" long barrel.
The classic example of this ambiguous terminology is of course the five-inch, thirty-eight-caliber gun, which, as spoken, could reasonably be parsed either way.
Late lunch hour was time to watch some Mythbusters; today, the "tossing pigs out of helicopters" edition.
As is often the case, I'm bothered by their treatment of the main myth: "It's sometimes possible to dodge a bullet fired at a distance" somehow morphed into "It's sometimes possible to dodge a bullet fired at a distance from a modern sniper rifle."
The results might have been very different if they'd used a different bullet-flanger. A Trapdoor Springfield, say, or Brown Bess, or even a .44 Magnum with a high-muzzle-flash load, rather than the latest high-velocity, low-signature technology.
And you'd think, after the pig toss, they'd have headed off into the sunset talking about making sausage....