Several times over the years the topic of variable scopes and ballistic reticles has come up.  The question is whether these hold over lines are accurate as your crank the power of your scope up and down.  In most cases the answer is no. 

The Burris Ballistic Plex and Leupold’s Boone and Crocket reticles are excellent examples of this.  Manufacturers publish easy to use charts for your caliber rifle and load and once you have determined the yardages for each line they are very quick and easy to use.  But you must remember that those numbers are only correct at one scope power.  If you are like me you crank your scope power down when in tight cover.   You need to remember to put your scope back to the proper power setting before trying to use those ballistic hold over lines.  With most manufacturers that setting is the max power, but not always.  One important factor I didn’t mention is that the center cross hair isn’t affected; it remains accurate throughout the power range.

Scope reticles are designed two ways.  They can be in the second focal plane (SFP) which is the way most hunting scopes are designed, or the first focal plane (FFP) which is more popular with tactical scopes and long range shooters.

The issue with the scope powers I mentioned above is only true for SFP reticles.  Scopes with FFP reticles remain accurate throughout the entire power range of the scope.  This may sound like a huge advantage, but there are drawbacks.  Here are some facts about the two.

Second Focal Plane:

• Hold over marks are only accurate at one scope power
• Reticle size and thickness remain constant at different powers, this is the reason for the inaccuracy
• Less expensive than FFP scopes

First Focal Plane:

• Hold over marks are accurate at any power
• Reticle size and thickness get larger at higher powers.  Tends to cover more of the target
• At lower powers the reticle gets very thin and difficult to see especially in low light

Above is a FFP scope, the mill lines do not change as the power increases.  However you can see how the thickness of the reticle has changed.

Above is a picture of a SFP scope, you can see as the power increases the point of impact for the 1 mill line has moved.

There are advantages to both types; the important thing is that you understand what you have and how to use it.  If you unsure what type your scope is there is an easy way to tell.  Look through the scope as you are adjusting the power up, if you see the reticle getting thicker you have a FFP scope. 

The FFP scopes are gaining in popularity, several of the higher end Leupolds, and the new Vortex Viper PST are both available in FFP, as well as most European scopes.  This article just touches on one point of how these scopes can affect the average hunter, when you get into the more technical details there are other advantages of each type of reticle.   Features such as mill ranging and having your mill reticle in perfect alignment with your turrets are also very important to long range shooters.

Like all other hunting gear it comes down to knowing what you have and gaining the skills to use it correctly.  It’s not so much how much you spend on your scope, but more so how much time you spend using it.