Due to the nature of anodizing aluminum, there can be significant variance in the resulting Dark Earth color. Lot to lot variance of materials, machining methods, surface preparation, and variables within the anodizing process all affect the final color.
While Nightforce maintains standards for the Dark Earth color, these standards allow some variation in color of the components of Dark Earth riflescopes and mounting accessories.
Color of rings on picture above is for demonstartion purposes only.