The LVT was originally designed to carry cargo and equipment to shore during amphibious beach landings during World War II. The US Marines quickly adopted the LVT as an assault vehicle and first used them against a contested beach during the invasion of Tarawa island. The original LVTs were not armored and the heaviest weapons they carried were the Browning .50 caliber M2HB. A more heavily armed assault version of the LVT was called for and the LVT(A) was created. The original LVA(A)-1 used the turret M3 Stuart light tank, but the 37mm gun proved to be ineffective against bunkers and other fortified positions. The LVT(A)-4 was upgraded with the turret from the M8 Scott 75mm GMC, which proved a far more capable weapon for supporting assault troops. The LVT(4) was also equipped with one hull-mounted .30 caliber MG and .50 caliber MG on the turret. This was often augmented with one or more additional .30 caliber guns for the turret crew.