155 mm gun T7

155mm L/40 T7
155mm L/40 T7
	T30 Heavy tank in Detroit Tank Arsenal, July 1950
Type	Tank gun
Place of origin	United States
Service history
Used by	United States
Production history
Produced	1940s
Variants	T7, T7E1
Specifications
Mass	2,384 kg (5,256 lb)
Length	6.64 m (21 ft 9 in)
Barrel length	6.4276 m (21 ft 1.06 in) (L/41.4)
Cartridge	155 × 775mmR
Cartridge weight	M107 HE: 94.99 lb (43.09 kg) projectile, 134.90 lb (61.19 kg) complete; M112B1 APBC-HE: 100.00 lb (45.36 kg) projectile, 139.90 lb (63.46 kg) complete; T29E1 APCBC-HE: 100.00 lb (45.36 kg) projectile, 139.90 lb (63.46 kg) complete; T43 (Mod.) AP:85.21 lb (38.65 kg) projectile, 125.11 lb (56.75 kg) complete; T35E1 HVAP:57.18 lb (25.94 kg) projectile, 97.09 lb (44.04 kg) complete;
Caliber	155 mm (6.1 in)
Rate of fire	3 rpm
Muzzle velocity	M107 HE: 2,352 ft/s (717 m/s); M112B1 APBC; T29E1 APCBC: 2,198 ft/s (670 m/s); T43 (Mod.) AP: 2,533 ft/s (772 m/s); T35E1 HVAP: 3,630 ft/s (1,110 m/s);
Maximum firing range	Project cancelled before maximum range tests occurred

The 155mm L/40 T7 was an American rifled tank gun developed in 1945. The T7 was to be the main armament for the T30 Heavy Tank, but only a handful were produced due to the T30 project being cancelled after trials in the late 1940s.

The T7 used two-part separated ammunition like the 105mm T5E1 gun on the T29 Heavy Tank. It had a low velocity of only 701 m/s (2,300 ft/s) compared to the 120mm T53 on the T34 Heavy Tank (945 m/s) and the 105mm T5E1 on the T29 Heavy Tank (945 m/s). However, the 43 kg (95 lbs) High-Explosive shell (HE) and high-velocity armour-piercing (HVAP) rounds were demonstrated to have a powerful demolition effect. Testing concluded before completion when the T30 project was cancelled in the late 1940s.