This is a 28mm model of the WW2 American T-19 Motor Gun Carriage, which was their first effort in making mobile 105mm fire support. A link explaining the history is here.
I started with previous remix of the accredited M3/M5 Half track, and created the storage and gun mount in the passenger compartment, working from photos i found online. I could not find a workable 105mm 3D model, so I cut out the 105mm from Bergman’s M-7, and crafted the elevation trunnions and elevation wheels, and cleaned it up to work. It sits on a post and does not need to be glued in.
I left the MMG mounts in the passenger area. If you wish, just clip these out of the hull on tinkercad. I left them in to allow a user the option to remove the 105 and place the HMG in the centre pintle and the two MMGs on the side of the passenger area and use the half track as a normal carrier; thereby getting double duty out of it. I included a historical pic of an M3 HT with the HMG so mounted; this was very common; as not all the HMGs were mounted in the “pulpit” mount next to the driver.
Be sure to check the photos for track placement; they fit tight and the driver sprocket goes to the front.