Small arms? I'd have preferred they use the Mk 45 5-inch/54 caliber lightweight guns, or at least the two Phalanx CIWS, the 2 triple 12.75 inch torpedo tubes (Mk46 torpedoes), the 2 25mm Bushmaster low-angle or the 4 12.7mm MG. (that's the .50 cals) that the both the Cape St. George mounts and the Gonzales mounts. (USS Gonzales is named after a Texas Marine!)
I think if the pirate ship was large enough, I'd go for the torpedos (that would be real shock and awe!), but otherwise the 5" and the 25mm Bushmaster. (Same gun used on the Bradely fighting vehicles by the Army).
We don't call 'em bushmasters. They're MK38s. Most of them were made by Bell Helicopters.