In an attempt to improve protection for the Commander when firing, 19 vehicles were fitted with the Model 74C turret housing two 1919A4 Browning Machine Guns. This was only ever an interim plan as there were plans to implement the T50 design as the standard turret for an Australian M113.
Australian M113s with the T50 turret began arriving in South Vietnam from August 1968 with just about every vehicle eventually fitted with the design.
The initial version of the turret housed two L3A3 machine guns (an improved version of the M1919A4), but some were later fitted with a M2 Browning and a M1919A3.
Initial feedback from the troops was that the turret was cramped, slow to rotate and was difficult to aim whilst the vehicle was mobile.
In an attempt to counter some of the issues the right-hand side L3A3 machine gun was removed from all the T50 turrets by early 1970. The weapon was instead fitted to the top of the turret using a pintle mount.
Interestingly, the Australian Army was only one of two operators to ever use the T50 turret.
Another unique detail with the Australian M113 was the armoured plate that was welded to the sponson above the first three road wheels on each side of vehicle. This was done in an attempt to offer greater protection against land mines. To further improve the safety of the crew another modification that was made from August 1970. A 38mm thick aluminium armoured plate was fitted to the underside of the vehicle. Whilst the plate added 680kg to the weight of the vehicle it proved to be a success, greatly reducing casualties from mine explosions.