Made a rival mag for a new project. Might as well also upload it. Dimensionally accurate but currently neither a 7 or 12 round magazine length. Profile features are accurate as I didn't need the length. I will update this in the future.
In the downloads is the STEP file for using the model and assembly freely. I only uploaded the STL to bypass Thingiverse's requirements.
Clarification: This is a magazine, I only tagged it with clip so the younger audience can find it.