Heckler&Koch MR556A1 - Manual (Page 8)

14 15
SECTION 4 — SIGHTS, SIGHT ADjUSTMENT, AND AIMING
MR556A1 rifles can accommodate a wide variety of optical and mechanical (iron) sights.
HK DIOPTER SIGHTS
For models with HK Diopter rotary sight sets, the sights are installed on the MIL-STD-
1913 (Picatinny) rail with a Phillips #2 screwdriver or the HK sight tool (Fig. 5 & 6). Do not
over tighten the screws.
Fig. 5 – Front Diopter Sight Fig. 6 – Rear Diopter Sight
For optimal sight use and the longest sight radius, the front sight is installed on the
most forward portion of the MIL-STD-1913 rail and the rear sight is installed on the
most rearward portion of the MIL-STD-1913 rail (located on the upper receiver). Sight
adjustment is as follows:
The sight adjustment is a rear sight adjustment, so the movement of the sight will be
in the same direction the shooter wants the impact of the round to move. If the hit is
to the right of the intended location, then the sights and the impact must be moved
left. Any corrections which may be required when sighting-in the weapon may only be
performed by adjusting the rear sight for elevation or windage. MR rifles are designed to
be sighted in at a range of 100 meters. REMEMBER THIS FORMULA: LL=C (Lower or Left
= Clockwise rotation)
ELEvATION ADjUSTMENT
Insert elevation adjustment tool into the rear sight cylinder so that the wedges of the tool
engage in the two slots in the cylinder which contain the catch bolts. Press Phillips-head
screwdriver downward into the adjustment tool and hold firmly. Rotate rear sight cylinder
manually in the desired direction (Fig. 7).
After correction withdraw Phillips-head screwdriver and remove elevation adjustment tool.
The catch bolts will then re-engage in the slots. After performing the elevation
adjustment set the desired aperture again.
NOTE: One-quarter turn of the rear sight drum will move the impact of the round
approximately 3.8 centimeters (1.5 inches) at 100 meters
Fig. 7 – Rear Fig. 8 – Clamping Screw Fig. 9 – Windage
Sight Adjustment (to tighten turn clockwise) Adjustment
ELEvATION ADjUSTMENT (Alternative method without sight tool)
Use of the HK Sight Adjustment Tool (HK ID # 300009) is always recommended to adjust
the windage and elevation on any HK firearms equipped with standard diopter sights.
However, some needle nose pliers can be substituted in the event that a sight adjustment
tool is not available to perform range adjustments.
Ensure that the MR556A1 is unloaded before performing any adjustment to the sights.
Use needle noose pliers with smooth jaws rather the serrated jaws as the serrated
surfaces may cause chips and burrs on the spring loaded catch bolts. Simply insert the
jaws onto the small shelf on the catch bolts and carefully squeeze while simultaneously
rotating the drum. This action withdraws the catch bolts and allows the drum to be
rotated either clockwise or counter-clockwise. To lower the point of impact, rotate the
drum clockwise and to raise the point of impact, rotate the drum counter-clockwise.
Ensure that the catch bolts engage the vertical slots located on the inside of the drum
after removing the needle nose pliers.
WINDAGE ADjUSTMENT
Point of impact, left: Loosen clamping screw on top of sight base (Fig. 8). Turn adjusting
screw on the right side counterclockwise (Fig. 9) in accordance with the required
correction. Then retighten clamping screw. This will move the impact to the Right.
Point of impact, right: Loosen clamping screw (Fig. 8). Turn adjusting screw clockwise
(Fig. 9) until the required correction has been performed. Then retighten clamping screw.
This will move the impact to the Left.
NOTE: Each revolution of the Windage screw will move the impact of the round 15.2
cm (6 inches) at 100 meters.
TROY ACCESSORY SIGHTS
Some MR556A1 rifles are supplied with Troy Industries Micro Folding Sights. Aiming and
sight picture are similar to using the HK diopter sights.
Fig. 10 – Installing front TROY sight Fig. 11 – Tightening front TROY sight
INSTALLING TROY ACCESSORY SIGHTS (FRONT)
1. Unscrew clamping assembly and place the sights at the desired location on the
Picatinny rail (Fig. 10).
2. Apply one drop of tread locking compound to the exposed threads of the clamping
screw. Replace the clamping plate and tighten the clamping screw while pushing
sight forward against the cross-slot (Fig. 11). To raise the sight, grasp and pull up
until the sights locks in the upright position. To fold the sight, depress the button on
the left side of the base and fold down. (Fig. 12)