It came attached to an Enfield mag that was in a box of stuff that I acquired a few years back. The only Enfield part in there. It’s patiently waiting for me to find an Intercepter. One came up for sale here about 6 months back. Complete and running, so probably should have grabbed it. They don’t seem to come up that often and my basket case situation is already out of control. Used the ring to mount a mag in the mill, so came in handy.