If you see a gun-toting character in the movies pull out his gun, keep his hand over the trigger and go bam-bam, then the chances are that the gun used is a sub machine gun. The various types of guns are:
Rifle: The name originates from the capacity of the barrel to rifle the bullet. That means, as the bullet goes out of the barrel, it imparts a spin to it. This helps the user to predict the direction and the accuracy of the bullet. In modern times, almost all weapons have a rifled barrel. Therefore products ranging from a small pistol to big guns like SLR can be termed rifle in technical terms. Example: the 0.303 lee-Enfield.
Assault rifle: An assault rifle has rifled barrel. It has an intermediate cartridge in between the pistol and the rifle. It can be fired from the shoulder. It can be adjusted to fire varied bullets depending upon the requirement, making it semi-automatic in nature such as AK-47.
Self loading rifle (SLR): The major difference between an SLR and the assault rifle is that it has only one firing mode. It fires only one cartridge at a time. The other features like shoulder mount fire, intermediate cartridge size and a rifled barrel are same as the assault rifle like American AR-15.
Read More at Blogspot.com