Mahan class destroyer

As built cira 1936:

• Gun director above bridge.
• 5 x 5"(127mm)/38cal guns in five Mark 21 DP pedestal mounts. ^[1] Mounts 51 and 52 were partially enclosed, and mounts 53, 54, and 55 were open. (pictured)
• 12 x 21"(533 mm) torpedo tubes on three four tube mounts. One tube mount was on the centerline between the stacks, and the other two were port and starboard just behind the aft stack.
• 4 x .50cal(12.7mm) Water Cooled AA in single mounts. Two on a platform just forward and below the bridge, and two on a deck house just forward of 5" mount No. 54.
• 2 depth charge roll-off stern racks.

cira 1944 (This varied from ship to ship depending on when and where they were refitted. See specific ship article for more accurate configurations − if available.):

• Mk33 Gun Fire Control System
• 4 x 5"(127mm)/38cal guns in four Mark 21 DP pedestal mounts. ^[1] Mounts 51 and 52 were partially enclosed, and mounts 53 (old 54), and 54 (old 55) were open mounts.
• 2 x Mk 51 Gun Directors for 40mm mounts.
• 4 x Bofors 40mm AA in two twin mounts. Replaced old 5" mount No. 53.^[2]
• 6 to 8 x Oerlikon 20 mm AA in six to eight single mounts. Four replaced the .50cal mounts, and two more mounts were installed in port and starboard gun tubs on the 01 deck just forward of the superstructure. On some ships, there were two additional mounts on platforms port and starboard of the after stack.
• 12 x 21" (533 mm) torpedo tubes.
• 2 x Depth charge roll-off stern racks.
• 4 x K-gun depth charge projectors. Port and starboard on the main deck next to 5" mount No. 53.