Look up the Warne 7.3 rings.
They are a dual clamp, one is for the metric one for the 3/8
I believe the dot on the clamp is up for 3/8 and down for metric.
They start at Medium
Visit Warne's site, look up your gun and they will give the recommends but I expect Medium will do fine .
Sportsmans usually has them at a good price.