This YouTube video from GunWebsites provides a basic introduction to the concept of "zeroing" an AR-15 rifle. Zeroing refers to aligning the rifle's sights so the point of aim matches the point of impact at a specific distance.

https://www.youtube.com/watch?v=Klvve0ZG_jo

The video explains five common zeroing distances (25, 50, 100, 200, and 300 meters/yards), illustrating how bullet trajectory curves due to gravity, impacting point of impact at different ranges.

https://open.substack.com/pub/gunwebsites/p/understanding-the-zero-a-comprehensive

The video uses graphs and target diagrams to visualize these trajectories for each zero, showing how the bullet's path varies depending on the chosen zeroing distance.

Finally, the video encourages viewers to visit the GunWebsites website for further information.