Need help adjusting front and rear sights for zero on No4 MK1/2

[Patrick Chadwick]

Is there significant backlash in your sight's elevation mechanism?

To correct for backlash, you must always approach the final setting in the same direction.

Example:

Set the backsight to bottom out.
Go up the number of clicks you need to be in the center (at whatever range you are using, 100 is good).
Check the POI. It doesn't have to be dead center.
Go up 5 clicks.***
Come down 5 clicks.
Shoot again, to check the POI.

If you cannot see any difference, then you are lucky.
Chances are, there will be a difference. Caused by backlash.

To allow for this, bottom out the sight, go up to the setting for 100, and repeat the POI check.
Go up 5 clicks.
But this time, come down 8 clicks, then go up 3 again. You do not have to bottom out the sight, just be sure that you "undershoot" the setting by more than any likely backlash. I reckon that if the backlash is as much or even more than 2 clicks, then you should get a new sight before wasting any more ammo.

The POI should be exactly the same as when you started (allowing for shooter and ammo variations).

In other words, since the "bottomed out" position is the fixed end point for the sight, you should always go up to the final setting, not down.

Finally, please note that this method requires that you have some adjustment leeway below the setting for the shortest range you are going to use If you ignore what Parashooter wrote and insist on carving your blade to be dead on at 200, you may find that the "undershoot" readjustment to 100 is no longer possible.

***If the backlash is more than 5 clicks, you need to bin the sight!