A ballistic calculator (online or phone app) can print a chart with the point of impact at 25 yards for a 100 yard zero.
There is little bullet drop for 5.56 in the first 100 yards, so most of the difference between point of aim and point of impact at 25 yards for a rifle zeroed at 100 yards is the error between the line of sight and the bore axis. The higher the scope is above the bore axis, the greater that error will be.
Here's a ballistic chart that I found online. The line of sight is 2.6" above the bore axis, so the point of impact at 0 yards is -2.6 inches. For a 100 yard zero, the point of impact at 25 yards is -1.6 inches.
There are online calculators that allow you to make your own chart using your own sight line above the bore axis, your own zero range, and even change the ammo or muzzle velocity. It's kinda fun and educational.
ShootersCalculator.com | 5.56mm
Calculates the ballistic trajectory of a bullet fired from a rifle, handgun or other firearm. Produces a ballistic trajectory chart and table that shows the drop, velocity, kinetic energy, windage, and trajectory of a bullet.
