The 2S7 is based on a large chassis that is probably the largest armored vehicle currently in the former Soviet inventory. The fully enclosed crew compartment is at the front of the vehicle and has seats for the commander, driver and two other crew members. The commander and driver are each provided with a circular roof hatch and in front of these are periscopes for forward observation. To their immediate front is a windscreen that, when in a combat area, is covered by an armored shutter hinged at the top. In addition, there is a single forward-facing periscope in the forward part of the roof between the commander and driver. The torsion bar suspension has seven dual rubber-tired road wheels either side with the drive sprocket at the front and the idler at the rear, and six track-return rollers that support the inside of the track only. Along either side of the hull are a series of large stowage boxes with the 203-mm gun, which is not fitted with a fume extractor or a muzzle brake, being mounted at the rear. One piston of the recoil brake and recuperator is located on the gun with the other two pistons beneath it and these limit recoil to a maximum of 1400-mm. The 203-mm gun is designated the 2A44 and when traveling is held in position by a manually operated lock mounted on top of the cab. The 203-mm rifled gun is fitted with a screw type breech block that opens to the right and is fitted with a large power-assisted loading device. The gun operator is seated at the rear of the hull on the left side with the elevation and traverse controls. It is reported that traverse is probably electric and elevation hydraulic, with manual controls being provided for emergency use. Ammunition is of the separate loading type, for example projectile and charge with a maximum muzzle velocity of 960 m/s. Maximum range, using unassisted ammunition, is 37.5 km.
The standard HE round is designated the ZOF 43 and weighs 43 kg with a total of four projectiles and charges being carried on the 2S7 for immediate use. The remainder of the ammunition load is carried by another vehicle, usually a truck. In addition to the HE projectile it is reported that other types of projectile can be fired including tactical nuclear and concrete-piercing and, possibly chemical. The 2S7 is provided with an ammunition-handling system that enables a rate of fire of 2 rds/min to be achieved, with this being operated by the loader. Mounted at the very rear of the 2S7 is a large hydraulically operated spade that is lowered to the ground before firing commences. Standard equipment includes an NBC system of the overpressure type and night vision equipment. An auxiliary power unit is not provided for the 2S7 so the main engine has to be kept running as a power supply during firing.
VARIANTS: The latest version is designated the 2S7M which has more recent communications equipment and can carry a total of eight projectiles and charges.