The 2S4 Tyulpan is fitted with a 240 mm mortar. The 240 mm smoothbore mortar, designated the 2B8, is carried complete with its base plate in the horizontal position on top of the hull and is pivoted at the rear. In the firing position, the mortar base plate rests on the ground. The 240 mm mortar has powered elevation from +50 to +80º with a powered traverse of 10º left and right. Just behind the driver position, there is a small turret for the commander which is equipped with an externally mounted 7.62 mm PKT machine gun. The mortar is fired by either electrical or mechanical means and two basic types of 240 mm mortar bombs are fired. A conventional high-explosive fragmentation bomb (3OF-864), which weighs 130 kg and has a maximum range of 9,650 m, and a high-explosive fragmentation rocket-assisted projectile weighing 228 kg with a maximum range of 18,000 m. The minimum range is 800 m. The 240 mm mortar has powered elevation from +50 to +80º with a powered traverse of 10º left and right. The rate of fire at +60° elevation is 1 round in 62 sec. and 1 round every 77 sec. at +80°. The 240 mm mortar system is aimed with a hydro-electric drive system by remote control. The mortar system 2S4 Tyulpan can fire a wide range of bombs as conventional high-explosive fragmentation, with a weight of 130 kg and has a maximum range of 9,5 km, high-explosive fragmentation rocket-assisted projectile with a weight of 228 kg and a maximum range of 18,000 m, nuclear and chemical munitions. Mortar bombs are kept in two drums located along the hull sides. Russian sources have stated that the tactical nuclear and chemical munitions are now no longer in service. The Russians also indicate that the 2S4 Tyulpan can fire the Smelchak laser-guided mortar projectile.

The hull of the 240 mm self-propelled mortar 2S4 Tyulpan is of all-welded steel armor construction that provides protection for the crew against the firing of small arms fire and artillery shell splinters. The 2S4 has a crew of four with the other five crew members being carried in the support vehicle. The mortar features a typical configuration and is arranged on the vehicle roof.