Most of the guns carried by such security are very old design lee-enfield rifles, some version of the AK-47 or sten guns. The police in India traditionally had 6 shot revolvers as standard issue for the officers. These work well as a visible deterrent when most people you are guarding against dont have guns. These guns are rarely fired by the private security guards. You will also see double barrel shot guns used by security personell at banks and atms.