Viseur Cobra

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Viseur Cobra

Message  LP13 le Sam 18 Aoû 2018, 11:04

Bonjour,
je dois régler le viseur "Cobra" de mon AK 74. Pas moyen de retrouver la notice, je ne sais même plus si elle était écrite en russe ou traduite en français.
Qui connaît le sens des corrections et la valeur d'une graduation ?
Merci par avance.

LP13
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Date d'inscription : 08/07/2012

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Re: Viseur Cobra

Message  viper65 le Sam 18 Aoû 2018, 12:02

ZERO


INTRODUCTION

Once you have attached the sight to the rifle, there are a few things you can do at home, that will make it simple and quick to do the final fine adjustment to zero the rifle at the range. First, make sure the clamp is secured tightly to the side plate, and adjust the clamp mechanism by changing the bottom screw setting if there is any play in the fitting. Do not overtighten.

OPTIONAL PRE-RANGE COURSE ADJUSTMENT

If the iron sights of the rifle have already been adjusted for zero, and the accuracy of the rifle has already been checked beforehand, you can do a rough zero at home of the Kobra sight with the mount attached, before spending excess ammunition at the range to accomplish the task. This can also be done indoors if you have at least 25 feet of room. I do this in my garage. Place the rifle in a bench vise or clamp, or other applicable secured mount that will ensure the rifle is not disturbed, by padding the receiver with wood blocks or leather strips, or cardboard, to protect the finish. Make sure you can remove or install the sight while the rifle is in the vise. Now, point the rifle at a distant wall or object (the farther away the better), and aim the iron sights to a specific point. You can tape a piece of paper up to this point, and have a friend use a marker to mark the exact spot the rifle is aimed to with the iron sights.
Now mount the Kobra, set it to dot mode, turn the intensity of the dot down until you can see just a small star sized point of light, and sight in on the dot your friend has marked on the wall. How far off are you from zero?
Both windage and elevation turret knob adjusters are located under protective caps on the rear of the sight. Pop both caps open Elevation is on the top, while windage is on the right side of the sight housing. Now you can use the following range procedure, at home, to adjust these knobs until the sight dot is aligned perfectly with the iron sights. This will give a very close estimate of zero, and when you get to the range very little will need to be done in order to bring the sight into fine tuned zero at 100 meters.

NOTE:

You can adjust the sight for major discrepancies between it's point of aim (POA) and the actual point of impact (POI) by loosening the turret adjusting knobs and manually rotating them around and around. There can often be quite a bit of tolerance in the installations of side plates between certain models of rifles, and it would be impossible to ensure these sights are close to zero out-of-the-box. But one virtue of the sight is that it is able to allow major adjustments to the reticule location than many high magnification sights can offer. Because this scope has no magnification, adjustments to the position of the reticule as it appears on the lens are almost visually invisible to the naked eye. You will not perceive that the dot moves by simply rotating the scale adjustment through it's standard clicks. At 100 meters an adjustment of the scale setting from 0-7 (to go all the way to the right) is only 8.5 inches total deflection (about 8.5 MOA) at 100 meters. This is 3,937 inches in range for an 8 inch adjustment (1:492 ratio). At you eye to the surface of the lens, about 5-7 inches, this would compute to a change in movement of the dot on the lens of less than 1/64th of an inch. Because this scope has no magnification, adjustments to the reticule position at the main lens are minute.

RANGE PROCEDURE: SIGHTING IN THE KOBRA

Elevation and windage adjustments on the Cobra are made via 2 adjustment wheels (referred to as "handles" in the manual) that are located under their protective caps on the top and right side of the Cobra. These wheels are numbered from 0-7 in both clockwise and counterclockwise directions and incorporate stops to prevent turning the wheels past '7' in either direction. Each number represents a change of 3.1cm @ 100 meters or approximate. 1.1 inches @ 100 yards. Under normal conditions, after the sight has had the initial mechanical zero set, these wheels will be used to make fine adjustments in the windage of the sight, and also for the range the target is located at (elevation).


INITIAL MECHANICAL ZERO ADJUSTMENT

Examination of the wheels shows a single-slotted screw at the exact center. This CENTER SCREW does not need to be adjusted in any way. Just outside this screw (referred to as "lead screw" in the manual) is another slotted SPANNER SCREW (referred to as a "nut" in the manual). This "nut" is only loosened on the Elevation knob if adjustments need to be made outside the stops of the wheels (see example below). This slotted nut is loosened by using the supplies special spanner wrench tool. For windage, the adjusting wheel has an OFFSET SCREW, that is actually the stop for the detent, and by unscrewing this small screw (not the center screw) about 3.5 turns, you can then spin this wheel without loosening any other screws on the windage wheel. NOTE: New versions of the sight may not have an offset screw, therefore the windage wheel on these models must be adjusted in the same method as the elevation wheel.

If you are adjusting for windage on the range, the suggested beginning range is 25 m/yds. Set the Cobra reticle to 'dot' and reduce intensity until you have the smallest and dimmest dot that can still be seen clearly. From a rest fire a 3-shot group. With the rifle 'on "safe" examine the target for deviation from your aiming point. Page 10 of the Cobra manual shows how to read the markings on the wheels to move your group closer to your aiming point. At 25m/yds each click or number change will move the impact point approximate 1/4". After sighting in at 25m/yds move back to 100m/yds and repeat the 25m/yd procedure.

After sighting-in you may wish the wheels to show '0'. This allows you to make field adjustments and still return to your original setting without difficulty. During the sight-in process you may need to adjust beyond the initial '7' stops of the wheels. To do this you use the double-prong end of the "screwdriver-wrench" tool provided in the camo carry pouch. Use the double-prong end to unscrew the slotted 'nut' about 1.5-2 turns. Now you can lift the wheel up and off the actual adjustment mechanism and rotate the wheel in either direction without moving the adjustment mechanism itself.

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Re: Viseur Cobra

Message  viper65 le Sam 18 Aoû 2018, 12:04


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