BS ISO 14135-2:2017 Optics and photonics. Specifications for telescopic sights High-performance instruments

Weapons
Optics
Outdoor sports equipment
Optical instruments
Visual perception
Interfaces
Optical properties of materials
Telescopic
Small arms
Dimensional tolerances
Classification systems
Tolerances of position
Performance
Telescopes
Tolerances (measurement)
Seatings

Link: BS ISO 14135-2:2017 Optics and photonics. Specifications for telescopic sights High-performance instruments
Source: BSI Standards