You can figure out sight and scope zoom multipliers by using patrol beacons.

Figured this out last night on patrol, when I was looking for an easier method than the current one to get the zoom multipliers for each sniper scope.

All you do is find the farthest distance that you can see the little numbers next to the patrol beacon from when you're ADS, and then divide by 15. It's worked with every sight I've tried to far. 15 is the normal number of meters away you have to be to see the numbers next to the patrol beacon.

For example, the TacSys sniper sight can show you the numbers up to, but not farther than, 90 meters away. 90/15=6, which is its zoom magnification.

Ambush, ViewTac, and ShortGaze all can see the numbers out to 73 meters, and 73/15=4.87, rounded to 4.9, which is their current magnification.

LongView SLR20 can show you the numbers from 105 meters, 105/15=7, and so on.

Just thought I would let y'all know, since this way seems to be a lot easier than having to analyze screenshots with distance measuring software.