Zeroing Your Scope
Low power variable optics or LPVO's such as the Tango6, ATACR and SnB 1-6x are great options for riflemen and marksmen alike. They offer low magnification for close quarters and 6x magnification for more extended distances allowing you to have the best of an optic like the ACOG and still retain your ability to engage targets are closer ranges similar to a reddot. Most of the time these optics come with useful crosshairs within the optic with range marks on them allowing for on the fly adjustments at varying ranges, making quickly aquiring and engaging targets at varying ranges easier...unless of course you aren't using 5.56x45.
What most people do not realise is that the lines inside of the scope are almost always calibrated to 5.56x45, meaning that unless you are using that round the lines will not be accurate however there is a simple way to remedy that. To do this you will need a range card and targets at 100m, 300m and 600m.
First of all, if you grab a scope like the [SigSauer] Tango-6 LPVO and look down the sight you will notice the BDC/Range lines or Bullet Drop Compensator lines, these are marked at 100m intervals in most scopes. Typically a chevron, dot or in this case a horseshoe will signify the 100/300m zero, for most calibers this will be dead on however once you stretch out to further ranges the other lines will not be accurate to your impacts making the lines almost entirely useless. By default, all rifles are given a 100m zero, so the center of the scope will be accurate at 100m no matter what however the other lines will not be - to resolve this we will be setting a 325m zero to our rifles.
First of all to figure out what number to set our scope to we will need to get ourselves a range card. In this case I am using .277 Fury out of the MCX Spear. As you can see below 300m is -0.9 and 350 is -1.2. We want something inbetween 300 and 350.
In this case I have gone with -1.1, that gives me a zero somewhere around 325m. That will then calibrate the center of my scope with my chosen caliber and then should also bring the other lines into calibration as well. Simple right? Try it out, your results may vary with certain scopes but in general it should work - theoritically if your scope is zeroed around 300m it should be the same at 100m and therefore zeroing your scope to around 300m should also zero the rest of the lines in your scope.
Don't believe me? Check out this video to see my results from doing just as I described. Keep in mind, that some guns and calibers will require trial and error to get the perfect zero. The velocities, barrel length and general capabilities of your caliber of choice will determine how well this method works.