I am not really aware of many if any special runs as we know them now that were made until recent years. The 7600 and its predacessors have been chambered in most all calibers that were popular along the way. However I think we will see special runs from now on. I hope they are not as limited as the 6MM was. Many years ago the 222 was used as a training rifle in the military. I have seen some of these which were heavy barreled models. That is training for match shooting.