They are factory gauges that replicate the custom 9mm spotting round used in that spotting rifle. Based on a 762 NATO case necked out to 9mm. The original rounds were fitted with a special 9mm flash head tracer round that replicated the trajectory of the main projectile. That was a whole development of its own.
You won't find these anywhere else as this custom round was specially developed for LAW80 and were never used on any other platform. These are unique and in great condition with signs of only light use.
Contact ideally by text or WhatsApp, otherwise by email.
Can deliver within about 10 miles drive, otherwise collect or post royal mail or something.