Yup, that dude that briefly shows on the screen at the beginning, looks to me like James Yeager. A polarizing firearms instructor. We're not gonna go there.
The Legend also briefly mentions DOPE, not drugs, but Data On Personal Equipment. In laymans terms, its what previous data snipers recorded that will help them make a first shot hit. IE. They made a shot with similar temperature, wind and distance and they held 5" to the left and 5" high to score a hit. Based on that DOPE, they will try and hold the same wind-age and use calculated risk to try and score a hit. Clear as mud?
Back to the video, i was in tears watching that....tears!