The X-frame between the ARVN Rucksack and Tropical Rucksack is a similar design but the Tropical rucksack’s one is a little bit longer. The ARVN is made by the canvas and cotton strap, the Tropical rucksack is made by Nylon with strap.
There aboves picture showing the differnce height of X-Frame between the Tropical 1968( Right in photo) and ARVN Rucksack (Left in photo), the structure of them are similar.
The prototype of both X-frame in 1:6 scale. The ARVN X-frame (Left side) which's the one applied in past Project 13007- Project Delta" Bullseye", the Tropical 1968 X frame (Right Side) will apply to the new Tropical 1968 in coming project. Both 1:6 X-frame are constructed by metal.
The new metal buckle will apply to the new production, the photo showing the 1:1 and 1:6 scale reference.