These are to allow the shooter to see the bullet holes in the target and to make any adjustments to sights and the shooters body position to ensure that the bullets are hitting the bulls eye on the shooters target. The minimum power for a scope should be 24x but these days most shooters are using variable power scopes up to 60x (shooting at 90Metres you need all of that to see the holes clearly). It should be noted that the cheaper the scope the less clarity it will have.
The only type that is recommended is a by-pod type NOT a tri-pod you can’t get them close enough to your eye to see down range without leaning over and this changes your body position.
Below are Pics of some members stands.