Reticle Perpendicularity

Aaron Spuler is a firearms enthusiast and recreational shooter. Follow more or his work at The Weapon Blog

Long range shooters go through great pains to properly set-up their rifles for long range shooting. Bipods, muzzle brakes, cosine indicators and a host of other widgets often adorn their newly created thunder stick. How many of them actually check to see that their scope reticle is perpendicular to the bore?

Often times they take for granted that the store clerk/gunsmith properly installed the scope and it is true to the rifle’s bore? Others often cant the rifle and set the reticle to what “looks vertical” in their opinion? The resulting misalignment can cause problems when we engage targets at long range.

Over the years I’ve watched shooters adjust both elevation and windage in apparent dead calm conditions. When queried about the “extra windage” they dialed, the excuses ranged from rotational drift, to the Coriolis effect? Never once did they question the possibility that the reticle was not perpendicular to the bore. Rotational drift at 500 yards is minimal (approx. 1.5 inches depending upon caliber and bullet) and is of no real concern to the long range hunter. Can you judge point of impact that accurately under field conditions? Probably not?

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