8-inch/30-caliber gun

8"/30 caliber Mark 1 & 2 Naval Gun
USS Boston's forward 8"/30 gun is in the right foreground, with its crew standing at their posts.
Type	Naval gun
Place of origin	United States
Service history
In service	1886–1906
Used by	United States Navy
Wars	Spanish–American War World War I
Production history
Designer	Bureau of Ordnance
Designed	1883
Manufacturer	U.S. Naval Gun Factory
Produced	1886–
No. built	Mark 1: 4 (Nos. 1–4) Mark 2: 4 (Nos. 5–8)
Variants	Mark 1 Mod 0 and 1 and Mark 2 Mod 1
Specifications
Mass	29,100 lb (13,200 kg) (without breech)
Length	257.99 in (6,553 mm) Mark 1 Mod 0 254.6 in (6,470 mm) Mark 1 Mod 1 255.6 in (6,490 mm) Mark 2 Mod 1
Barrel length	240 in (6,100 mm) bore (30 calibers) 244.78 in (6,217 mm) bore 30 calibers
Shell	260 lb (120 kg)
Caliber	8 in (203 mm)
Elevation	−5° to +20°
Traverse	−150° to +150°
Rate of fire	0.5–1 round per minute
Muzzle velocity	2,000 ft/s (610 m/s)
Effective firing range	14,000 yd (13,000 m) at 20° elevation

The 8"/30 caliber gun (spoken "eight-inch-thirty-caliber") formed the main batteries of the United States Navy's "New Navy". They were a US naval gun that first entered service in 1886, and were designed for use with the first three protected cruisers, Atlanta, Boston and Chicago.^[1]