The Tommy used a fixed ejector riding in a slot in the bolt, very similar to the AK setup in principle. Since the square rear section of the bolt riding in the receiver kept everything aligned, they went with a much simpler ejector instead of a rail. Just a threaded hole in the left side of the Tommy receiver and a screw with a flattened end is screwed in. To keep the flat properly aligned the head of the ejector screw was a small oval shaped flat spring steel piece with a dimple in it. This dimple fit into a shallow hole on the outside of the receiver to index it properly.