What are advantages of first focal plane scopes?

First Focal Plane Advantages

First focal plane scopes are designed to compensate for bullet drop and wind deflection at any magnification power. This is achieved by calibrating the reticle to match the ballistic trajectory of the bullet at 1x, or the lowest magnification power. The resulting subtensions allow hunters to quickly estimate holdovers and wind deflections, reducing the need for complex ballistic calculations.

Parallax-Free Shooting

One of the key benefits of first focal plane scopes is parallax-free shooting at any magnification. This is achieved by placing the focal plane of the reticle at the first focal point of the objective lens. By doing so, the reticle remains sharp and clear at all magnification powers, eliminating the need for hunters to adjust the parallax correction every time they change magnification. This results in more accurate shots, especially at longer ranges.

Subtension and Holdover

First focal plane scopes also provide improved subtensions for estimating holdovers and wind deflections. By calibrating the reticle to match the ballistic trajectory of the bullet at 1x, hunters can quickly estimate the distance between the bullet’s impact point and the target’s center, allowing for more accurate shots. This is particularly useful for long-range hunting, where small errors in holdover can result in significant differences in impact. For example, a 1 MOA (minute of angle) error at 500 yards can result in a 5-inch difference in impact, highlighting the importance of accurate subtensions in first focal plane scopes.