The 2B16 is a 120-mm towed combination mortar-howitzer. The ordnance is likely a towed variant of the ordnance of the 2S9 120-mm Self-propelled Combination Gun. When in the firing position the 2B16 Combination Gun is supported on a small circular baseplate located under the forward part of the carriage with the wheels raised clear of the ground, and on the two trails. The trails are of a box section and locked together at the rear for towing, probably by a GAZ-66 (4 x 4) 2 ton truck which also carries the crew and a quantity of ready use ammunition. The ordnance is fitted with a large multi-baffle muzzle brake with the recoil system being mounted above the ordnance and extending about half-way along the barrel. When in the traveling configuration the ordnance is withdrawn out of battery to the rear to reduce the overall length of the system. A thin shield is provided either side of the ordnance to give some protection to the gun crew from shell splinters with the left side of the shield being slightly higher than the right as this also protects the sighting system. The upper part of the shield can be folded forward through 180° if required, although there is an aperture in the shield for the direct fire telescopic sight. The elevation and traverse handwheels are located on the left side of the carriage as are the direct and indirect sights. The breech is of the vertical sliding type and what appears to be a chamber indent device is fitted to retain the round in place when the weapon is fired at high elevation. It is believed that a power rammer is normally fitted to assist in loading ammunition at higher elevations as well as increasing its rate of fire.
The 120-mm gun has a rate of fire of 6 to 8 rds/min. The direct fire HEAT projectile is estimated to defeat up to 600-mm of armor. In the indirect fire role the mortar fires high explosive, white phosphorous and smoke rounds. According to former Soviet sources, the maximum range of the 120-mm weapon is some 8000 m. Mounted below the turret rear is an ammunition loading hatch and mounted on top of the hull is a device for loading ammunition from the ground directly into the fighting compartment. This allows sustained fire missions to be carried out whilst still retaining onboard ammunition supply.