I shoot in the Midlands league, with air rifel. I use a Weaver T36 or a Bushnell 4200 8-32x40. I prefer the Bushnell as it is more versatile. Some shooters use 12, 18 &24 mag scopes with similar success.

Rules vary considerably for Benchrest, best to find a club and check the rules they shoot to.

Most importantly join in and enjoy it!