Rifle Scope Product

Overview

A rifle scope is a telescope built to survive recoil while holding an aiming mark in precise registration with the rifle's bore. Light enters through the Objective Assembly, whose Objective Doublet forms an inverted image inside the Main Tube. The Erector Assembly re-inverts that image and varies magnification, and the Ocular Assembly presents the result to the eye together with the aiming pattern on the Etched Reticle Glass.

The whole optical train lives inside the Tube Body, a one-piece 6061-T6 aluminium tube machined with an integral Turret Saddle. After assembly the tube is evacuated through the Nitrogen Purge Screw and backfilled with dry nitrogen, so no internal surface can fog when the scope moves between a warm vehicle and a cold range. An O-Ring Set seals every joint, turret shaft, and the Battery Cap.

Optical train

The Objective Doublet is a cemented achromat: a crown-glass positive element bonded to a flint-glass negative element so the red and blue focal points coincide. It sits in the Objective Bell, clamped by a Lens Retaining Ring with a ground Lens Spacer Ring holding the design air gap. The doublet forms a small inverted image at the first focal plane.

Because that image is upside down, every rifle scope contains an erector system. Two lens cells inside the Erector Tube relay the first image to a second focal plane near the eyepiece, flipping it upright in the process. The same cells provide zoom: each Zoom Lens Cell carries a Cam Follower Pin riding in a helical slot of the Zoom Cam Tube. Rotating the Magnification Ring about half a turn drives the two cells toward and away from each other, sweeping the system from 4× to 16× while keeping the image focused.

The Eyepiece Lens Group magnifies the second focal-plane image at about 90 mm of eye relief — far enough that the ocular bell does not strike the brow under recoil. The Fast-Focus Diopter Ring shifts the group over roughly ±2 dioptres to focus the reticle for the individual eye, and a Rubber Eyecup blocks stray light.

Adjustment mechanism

Zeroing a scope means tilting the erector tube. The tube hangs from the Erector Pivot Gimbal at its rear and is pressed by a Coil Spring against two spindles entering through the saddle at 90° to each other. The Elevation Turret sits on top, the Windage Turret on the right. Each turns a fine-pitch Adjustment Spindle — at 0.5 mm pitch, one full turn moves the spindle tip half a millimetre, and the geometry of the erector pivot converts that into a known angular shift of the point of aim.

Each click is generated mechanically: spring-loaded balls (a standard Ball Bearing pair under a Coil Spring) drop into grooves of the Click Detent Ring, giving one tactile and audible detent per 0.1 mrad. The Turret Knob lifts and re-clocks so its engraved zero aligns with the sighted-in position, and the Zero-Stop Shim is then set as a hard floor — the shooter can always dial back to zero by feel, even in the dark.

The third knob on the saddle, the Parallax Knob, moves an internal focusing element so the target image falls exactly on the reticle plane. When the two planes coincide, small head movements behind the eyepiece no longer shift the crosshair against the target; the marked range scale runs from 25 m to infinity.

Reticle and illumination

This is a second-focal-plane design: the Reticle Cell sits between the erector and the eyepiece, so the crosshair stays the same apparent size at every magnification. The pattern is photolithographically etched into the Etched Reticle Glass rather than built from stretched wires, which is why modern scopes survive the 1000 g recoil spikes of magnum cartridges without a broken crosshair. At assembly a Reticle Alignment Shim rotates the cell until the vertical stadia tracks the elevation spindle exactly, then the Reticle Lock Ring is torqued down over thread-locker and held by the Reticle Mount Ring.

For low light, the Illumination Module module edge-lights the etched pattern. A Reticle LED fires into the polished edge of the glass; light is trapped by total internal reflection and escapes only where the etched grooves scatter it, so the shooter sees a glowing reticle over an otherwise dark field. The Brightness Dial steps the LED current through 11 levels with off-positions between each, and a CR2032 Coin Cell behind the sealed Battery Cap runs the system for around 300 hours. The small driver circuit lives on a Bare PCB connected through a Wire Bundle routed inside the saddle.

Mechanical integrity

Every adjustment must return to the same place after thousands of recoil cycles, so the moving parts are deliberately stiff: the erector spring preloads the tube against both spindles at all times, the lens cells are torqued and staked, and the entire assembly is proof-tested on an impact machine before the nitrogen fill. A Fastener Set of small thread-locked screws secures the saddle hardware and ring stops.