Disclaimer: I am a student, not an expert, and these are my
sniper class notes. If you need an expert, consult any gun forum, they all
claim to be rifle experts.
Choosing the best target rifle scope for 1,000 yard competitions
requires these features:
- A 20x magnification
- Tall target turrets
- Side Focus
- 40 mm objective
The scope ,must have no greater than a 40mm objective (to mount
low and not lose "cheek weld") plus a side focus (parallax).

Leupold VX-III
6.5-20x40 LR 30mm with Target Turrets and Side Focus (model 55146).
Unfortunately, they no longer makes this model and you need to find a
used Leupold scope:
- Leupold VX-III 6.5-20x40 LR 30mm with Target Turrets and Side
Focus (model 55146).
- Leupold VX-III 6.5-20x40 (model 51426).

This is yhe correct used model to find:

If you cannot find this scope, the only other option is to buy a
16x40mm Leupold and send it to an optics expert to be "bumped" to 20x
power.
EFR stands for "Extended Focus Range".
NF stands for ??