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 ?
In part one of this series, we covered how to choose the best peep sight aperture size for your applications.
I mounted a Bushnell 1.25-8x Elite 6500 scope in low Burris Signature rings for testing, and the scope cleared the rear sight aperture easily.
Using an end mill, I opened the rear sight aperture just a bit, making it a more practical hunting sight.
If it feels as though your sight aperture is simply too full, the best bet is to downgrade in pin count.
I like a larger peep to center my sight aperture ring and allow as much light in as possible.
Because the lowest sight aperture was 150 meters, it was expected that at our chosen range of 50 yards the rifle would shoot high.
While the hood is not present, the rear sight aperture is a finer .052 inch.
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.
Put one or two drops of CLP in the hole in front of the rear sight aperture and on each knob.
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.