After using my Sd251s and Sd234s I realized I needed a couple more, cheaper units, to throw into battle as “disposbale guns” that I didnt mind losing if they never got a shot off. I also got tired of my 75mm AT guns being too weak, and my 88 flaks being too easy to hit, so I made my fav gun, the low-profile 88mm high-velocity AT gun by adding a nashorn gun to the base of a 75mm gun. I included a 75mm gun in the pic for comparison to my new 88. No worries, the Nashorn which lost its gun to make this, was put to good use - it became a Hummel.
I was short on 75mm guns too, so 1 of these RSO’s is short a gun yet, to be made and added later.
I made the RSOs by chopping Marders down to just the treads, and enough of the front and back hull to hold them together. Clear plastic (cut from a football card protector and sanded so glue would work on it) is the base for the superstructure, and provides the surface to mount the gun on. Balso is what the superstructure is made from, and paper is used extensively in it, especially to makes the hull sides smooth. Brass is used for the drivers seat. When I used my reference pics I noticed thier is stuff on the sides of these, not sure if it is loose legs for the guns, or some form of apparatus for folding the sdies of the vehicle down. But in either case, I just used some pieces from old model ships that gave an approximate look, and they are not 100% accurate. I just didnt like the completely flat sides I had, and had to add on something.