Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online.A huge number of M113 Armored Personnel Carrier variants have been created, ranging from infantry carriers to nuclear missile carriers. The M113 armored personnel carrier has become one of the most prolific armored vehicles of the second half of the 20th century, and continues to serve with armies around the world in many roles.Australian AFVs have the suffix "AS" often appended by a model number, the "AS" is a NATO code for Australia. Generally speaking Australian models are modified from the original models, in the case of the M113A1 series this included the AN/VIC-1 communications harness, large dust filters for the passenger compartment ventilation blower, heavy steel track manufactured by ADI, provision for 600 kg of belly armor, the Cadillac-Gage T-50 turret mounting twin .30 Brownings(early service) or a .30/.50 Brownings machine guns for APC/LRV versions, a traverse bar to prevent the crew commander traversing the turret to the rear over the troop compartment roof hatch with the guns depressed low. For some reason all version of the M113A1 had the passenger compartment heaters removed except the M577A1 command vehicle.