What is sfp. And how does it work? — 1 Answer

There are two types of focal plane scopes. There is first focal plane (FFP) and second focal plane (SFP). In a FFP scope the reticle is mounted in the scope past the magnification lens. In a FFP scope the reticle will increase in size as the magnification increases and then shrink in size as magnification decreases. In a SFP scope the reticle is mounted before the magnification lens so the the reticle will stay the same size no matter what magnification you are using. In an FFP scope the reticle holdover marks are accurate at all magnification levels. In an SFP scope the reticle holdover marks are only accurate at the highest magnification level.