I have a CETME.
There is no mag wobble, zero, nada, zilch when using the original CETME magazines. They lock up mucho tight.
There is no mag wobble, zero, nada, zilch when using the G3 magazines. They lock up even more mucho tight. They usually require a sharp rap on the bottom to lock in place.
In fact, the magazine is firmly inserted inside a 4 sides magazine well, I dont see any room for a magazine to wobble.