I took the ATD out to my shop tonight to clean it and took some pictures.
Looking into the underside of the action, you can see the cartridge-shaped magazine follow up against the top of the receiver. The latch at the rear of the forearm keeps the barrel indexed when the rifle is assembled.
Here’s the magazine tube insert partially withdrawn for loading. You can also see the funnel-shaped port on the right side of the butt. That’s where you drop cartridges into.
Here’s the buttplate and the end of the magazine tube insert. Norinco left some wood unfinished there. I need to seal it.
Here’s the mag tube insert pulled out of the gun, along with the trigger guard/bolt group.