Vernier sights are important components of firearms, helping to improve the accuracy of rifles over a longer range. Sights are fixtures attached to firearms which help the user to aim at a target.
The most basic type of sights were the Iron sights which were made up of two metal blades placed in the line of sight of the user. These type of sights were fixed in nature which meant their accuracy wasn’t great at longer ranges.
With improvements in firearm technology and the introduction of rifling, gun ranges began to increase and thus came the need for adjustable sights. Adjustable sights were required because a bullet does not travel in a straight path over a long range.
This is because of the principles of projectile motion in which the effects of gravity cause the bullet to lose height. Also wind direction can cause the bullet to deviate horizontally in its path. To counter these effects, the gun has to be aimed slightly higher for longer ranges and to do this requires adjusting the position of the sights.
Adjustable sights consist of a movable rear sight post attached to a graduated vernier staff scale. This scale is usually graduated in increments of 0.05 inches. The movable part known as the eyepiece contains five or six marks spaced 0.04 inches apart. These two components give them the name of vernier sights since they work in a similar way to the vernier caliper.
The smaller sliding scale moves on the larger scale and the alignment of specific marks on the scales determines the value of the reading.
The graduations on the vernier staff scale are assigned 5 points each with each point representing 0.01 inches. The readings are measured similarly to a vernier caliper. For example to adjust the height to 30 points, the slider is adjusted so that the zero mark on the slider aligns with the sixth mark on the scale.
For 31 points the slider is moved till mark number 1 aligns with the scale and this way the position is set for any value of points between 0 and 100. For a sight radius of 36 inches each point would cause the bullet impact to move 1 inch per 100 yard range.