I ran convoys in Vietnam in 1969. We had armored gun trucks the units built to fight back against ambushes. I had several in each convoy. I had an armor plated gun jeep. No one makes a model of the M-54 five ton so I had to do my own, making masters and casting the parts. I used the Italeri M-925 US Army 5 ton model for the frame(had to modify it also). I have been making the gun trucks that were in my company. You can read about the build of the Red Baron here: http://thescrr.com/GunTruck/
Scroll to the bottom of the page and you will find a link to my build of Snoopy.