All the time we have customers in looking at optics for their guns. One of the biggest questions we get asked is what we would recommend for a rifle when they want to go with a LPVO. On top of all the brands it can be intimidating to also have to make decisions of range of magnification, price, size, and weight. Most people with all of that going on don’t realize that there is one other huge factor that they need to decide on as well. That factor is First Focal Plane (FFP) and Second Focal Plane (SFP).
Most of the time the only Scope anyone has looked through has always been SFP, FFP has become more and more available as more companies offer the option. Vortex has been innovative in their designs and options and offer the FFP option in a variety of there optics.
Lets get into it, on the option of SFP the glass that has your etched reticle is in the rear of the Optic after the erectors. The option of FFP is in front of the erectors in the tube. This makes it so that when you zoom in on FFP the reticle also gets bigger. With most scopes that means that they have now been able to add very fine detail to the reticle that allows for you to get an amazing amount of ballistic data as you zoom. With this data you can make quick adjustments to take farther shots. Another other upside to FFP is that as you zoom your holdovers never change. When you adjust your magnification on SFP the holdover on target changes with each magnification. When you look at the illustration below this shows how holdovers change with increased magnification. They are all at 300yrds with a 20mph crosswind on a Vortex Strike eagle 1-6. They are at 1x, 3x, and 6x magnification.
A very big piece of information that needs to be addressed on FFP Scopes is that because of where the glass is located you must be very and I cannot stress this enough VERY careful not to over torque your scope rings you run the risk of the class being in the same location as a ring and if you over tighten them you can break the glass internally. Most optics companies will not warranty the issue if its due to you being careless also. So refer to your installation instructions or have a licensed gunsmith help you out.
I hope that you have found some of this information useful, and that it will help when making decisions on new optics for your setups. There is also a video on YouTube that explains this in detail that may help as well.