sight aperture

sight aperture

[′sīt ‚ap·ə·chər]
(ordnance)
An irregularly shaped, adjustable, mechanical item usually integral to a rear sight; it functions as a peephole through which the sight at the opposite end of a gun is brought into view in aiming at a target or object.
References in periodicals archive ?
Slide the sight aperture all the way forward, remove the hinge pin at the front and voila, the leaf slides out and the new one slides in.
Long-gun accessory offerings for 2012 include the AR-15/M16 Same Plane Sight Aperture, Offset Flashlight Rail Mount, Single Point Sling Adapter, AR-15/M4 Storm Sling Adapter and Twist Lock QR Sling Swivel.
This gap between the string and your peep sight actually creates an opening a lot bigger than any peep sight aperture.
Using a round pin guard allows you to center the entire sight aperture inside the peep instead of an individual pin, giving up nothing in accuracy but gaining a low-light edge.
To overcome gravity, the rifle is angled slightly upward, but the LOS is not because, by definition, it is a straight line from the eye, through the sight aperture or optic to the target.
Put one or two drops of CLP in the hole in front of the rear sight aperture and on each knob and turn the knobs until they move smoothly.
The rear sight assembly will mist the eye of the M1917 Enfield fan, having prominent ears protecting the sight aperture.
Once in your tree, check for snow and ice in or on cams, roller cable guard, arrow rest, peep sight aperture, and sight pins.
The Soldier then folds down his rear sight aperture and his CCO is "mostly" zeroed.
Knowing the advantages of a large rear sight aperture for hunting, I've left the screw-in sight aperture out of the sight.
In the quest for a brighter sight, Trophy Taker first applies military-grade, photo-luminescent tape to the sight aperture and then wraps 50 inches of green fiber around the tape.