Longbow Night Vision System Instruction Manual 1
Longbow Telescopic Sight Technical Description
The Longbow scope is a 2.5 x -10 x variable magnification telescopic sight with a 56mm objective lens. It has a Mil- dot reticule with stadia marks, and indexed windage and elevation drums, which are 1/4 minute click adjustable. For low light use, or dark target areas, the whole reticule has a variable illumination facility. The scope has a parallax adjustment, which can also function as a basic range finder up to 200 yards.
The reticule is in the front focal plane so that the Mil - dot marks maintain their relationship with the target no matter what the magnification setting. The lenses are multi - coated with anti reflective chemicals to increase light transmission through the scope.
The ocular unit aft of the power adjustment ring is removable to allow the fitting of an infra red night vision unit to the scope. This facility allows the scope to be used in all conditions where rifle options are technically feasible.
Zeroing and Drum Adjustment
The scope is mounted onto the weapon by the most secure mounts available. It is unlikely to work loose, check it anyway!
The scope has virtually no fore and aft fitting range due to the ring spacing being only just narrow enough to fit onto the scope tube without fouling the ring. This means that all the adjustment to accommodate the firers physique to get the correct eye relief must be done by butt plate adjustment.
Having fitted the weapon to the firer, to zero the weapon, progress through the following stages;
1. At 100 yards fire a 3 round group with minimum 2 minutes (time) between shots.
2. Indicate group centre and dial up turrets to move group centre to centre of target.
3. Fire 2nd three round group as at 1. /After 5 minute (time) gap.
4. Repeat step 2 as necessary.
5. Repeat step 3 as necessary.
6. When you have hit the centre with two consecutive three round groups, the weapon is considered to be zeroed.
7. Adjust drums as required to set up index facility.
NB.
1. The time delay between shots is to minimise barrel warm up to give as close to a cold barrel zero as is practically possible.
2. The precise establishment of a precise 100 yard zero is vita! to an accurate elevation plot for longer ranges.
Drum adjustment
1. Slacken 4 hex sctews on the drum to be adjusted.
2. Turn drum to set '0' to the index line without 'clicks' being apparent.
3. Press drum onto shaft and tighten 4 hex screws.
4. Set up record of zero for individual weapon by drawing record card.
