NRA NRA Sight Systems & Optics 2

Question 1

A rifle scope marked '3-9x40' indicates which combination of specifications?

Accepted Answer

3 to 9 power variable magnification, 40mm objective lens diameter

Answer

In standard scope notation, the numbers before 'x' indicate the magnification range (3× to 9×), and the number after 'x' is the objective lens diameter in millimeters (40mm).

Question 2

What is 'eye relief' as it applies to rifle scopes?

Accepted Answer

The distance between the eyepiece and the shooter's eye that produces a full, clear field of view

Answer

Eye relief is the specific distance the shooter's eye must be from the ocular lens to see the full sight picture; insufficient eye relief can result in scope bite (injury from recoil).

Question 3

In a first focal plane (FFP) variable scope, how does the reticle behave when magnification is changed?

Accepted Answer

The reticle grows and shrinks proportionally with changes in magnification

Answer

A first focal plane reticle is placed before the magnification erector system, so it scales with the image — its subtensions remain calibrated and accurate at every power setting.

Question 4

What is parallax error in a rifle scope, and when does it occur?

Accepted Answer

The apparent movement of the reticle relative to the target when the shooter's eye moves off the optical axis

Answer

Parallax error occurs when the target image and reticle are focused on different planes inside the scope, causing the reticle to appear to shift relative to the target as the shooter's eye position changes.

Question 5

What is the function of a rifle scope's windage adjustment turret?

Accepted Answer

To move the reticle or impact point horizontally left or right

Answer

The windage turret moves the scope's reticle (and thus the point of impact) horizontally, allowing the shooter to correct for left or right deviations caused by wind or mechanical offset.

(NRA) National Rifle Association Certified Gunsmith Practice Test

(NRA) National Rifle Association Certified Gunsmith Practice Test

NRA NRA Sight Systems & Optics 2