The MO-120 RT-61 120mm rifled mortar, or Mortier 120mm Rayé Tracté Modèle F1, is a heavy mortar of French origin. Thomson-Brandt designed it to be the successor to the MO-120-AM-50. The “RT” in its designator stands for rayé, tracté, meaning rifled and towed. The RT-61 rifled mortar is currently being used by the French Army, and is produced under licenses by Italy, Belgium, Germany, the Netherlands, Brazil, Turkey, and Japan.

In French service, the MO-120 RT-61 rifled mortar is normally towed by the VTM 120, a wheeled armored vehicle derived from the VAB 4×4 series of armored personnel carries. A towing hitch is screwed onto the muzzle of the weapon for towing purposes. The VTM 120 also carries up to 70 rounds for the mortar and offers protection from shrapnel and small arms fire for the crew. Originally equipping infantry regiments, the mortars have now been transferred to artillery regiments, where they augment the 155mm towed artillery.

Most militaries generally rely on three classes of mortar protection – 60mm, 1mm, and 120mm calibers. The 120mm systems offer the most power at longer ranges. As a 120mm system, the MO-120 RT-16 rifled mortar weighs in at 1,283 pounds with a barrel measuring in at 9 feet, 2 inches. The rifled launch tube fires 120mm, 41-pound projectiles out to effective ranges of 8,900 yards and rocket assisted projectiles up to 14,000 yards. Its support assembly provides and elevation span of -30 to +85 degree firing angles with traverse from the centerline of +/- 14 degrees. The rate of fire ranges from 6 to 10 rounds per minute.

The MO-120 RT-16 rifled mortar was developed to fire standard NATO mortar projectiles. It also features two modes of fire built into its design: the initial function is the standard mortar “drop-and-fire” approach and the alternative function is a delayed, lanyard-actuated feature. The latter offers more direct control to be given to the operator.