One of the features on many of the V100's with turrets used in Viet Nam was the twin M73 machine guns. They were known for being unreliable and many of these turrets were fitted with field installed M2HB's that required the soldier to be outside the turret in order to fire it.
Today the M73 is in very limited supplies as most were scrapped. However if you are performing a correct restoration, these things are required. Here's the M73 replicas we're building for the restoration we are doing on the Blood Sweat and Tears V100 that did serve in Vietnam. We are building the entire dummy gun for applications where the M73 was either a coaxial weapon or where a pair were intended to serve as primaries.
If any of you are or know of any Vietnam vets that may have photos of the V100 with "Blood Sweat and Tears" nose art while in Vietnam, I'd love to hear from you.
https://www.facebook.com/Blood-Sweat-and-Tears-V100-Vietnam-Military-Police-104355265507200