weapon motar

Design
Most modern mortar systems consist of three main components: a barrel, a base plate, and a bipod.
Modern mortars normally range in caliber from 60mm (2.36 in) to 120mm (4.72 in). However, mortars both larger and smaller than these specifications have been produced. An example of the smaller scale is the British 51 mm Light Mortar which is carried by an individual and consists of only a tube and a base plate. Conversely, a large example is the Soviet 2S4 M1975 Tyulpan (tulip flower) 240mm self-propelled mortar.

Smaller mortars (up to 81 mm) are commonly used and transported by infantry based mortar sections as a substitute for, or in addition to, artillery.
Ammunition for mortars generally come in two main varieties: fin-stabilised and spin-stabilised. The former have short fins on their posterior portion which control the path of the shell in flight. Spin-stabilized mortar shells rotate as they travel along and leave the mortar tube. This action stabilizes them in much the same way as a rifle bullet. Both types of rounds can be either illumination (infra-red or visible illumination), smoke, or high explosive.

Spin-stabilised rounds require a rifled barrel. Since mortars generally are muzzle loaded, the mortar shell has a pre-engraved band, called an obturator, that engages with the rifling of the barrel. The increase in accuracy is offset by an increase in loading time and accounting for drift; a peculiarity of rifled systems that causes the round to "drift" perpendicular to the spin axis; this Magnus effect is common to any spinning projectile, and is, for example, what makes it possible for pitchers to throw curve balls.

One of the advantages in the use of mortars is the volume efficiency of their casing. While this doesn't hold true for rifled mortars, the smooth-bore models (as they do not have to withstand the rotational forces placed upon them by rifling) can be designed with much thinner skins, increasing the explosive load they can carry. Due to the difference in available volume a smooth-bore mortar of a given diameter will have a greater explosive yield than a similarly sized artillery shell. An excellent example is the comparison of a 120 mm mortar and a 155 mm artillery shell which have almost identical explosive capabilities.

Mortars come in a variety of calibers. The French 81 mm mortar became standard for many countries. The Soviets took advantage of this by standardising on 82 mm mortars. This allowed troops using Soviet mortars to use mortar ammunition of other countries found on the battlefield, albeit with less accuracy, while their own would be too large for their opponents. This advantage was used during the Vietnam War and at other times