duster(1)the M-42. It was an automatic twin 40mm "ack-ack" set up on a tank body. It was used for firebase and convoy security. 2) WWII tracked vehicles brought to RVN. They were medium size and sported two 40mm pom-poms plus one M60 Machine Gun, plus a crew of about 4 to 5 with individual weapons. They were used for convoy security and perimeter security for artillery bases each night. D-50)
