Thanks.
I found a supplier of front sights for CZ 550. So I can now equip myself with a new front sight, that will make my CZ zero in a 410 grain bullet at 50 meters.

Now... From where to where do I measure the height of a front sight?
Do I measure to the bottom of the bead?
Do I measure to the middle of the bead?
Do I measure to the top of the bead ?

And where do I measure from?

My rear sight is a standard V shape which I have used with the bead "lying" on the V, covering the target. So to my recollection, sight height should be measured to the bottom.

Once I have found this out I secondly need to calculate what height I need.

How do I calculate the right heigt of the front sight?

Thanks for any help.

Niels

I take a stab at the math. I would draw a long thin triangle. The bottom side represents a line from the rear site notch (point a) to the target bullseye (point c). The upper corner of the triangle (point d) is where the bullet now strikes. Along the line somewhere between (a) and (c) place a (point b). (b) will represent the bottom of the front bead. Now you have two lines from the rear notch one threw (b) onto (c) the target and other to (d) actual impact. This formula will give you the CHANGE or added height needed for your replacement front site.

change in height in mm =

(d->c, shooting error in mm) * (a->b, rear to front sight in mm) / (a->c, 50,000 mm)

Agree?

quote:

Originally posted by Niels:
Thanks.
I found a supplier of front sights for CZ 550. So I can now equip myself with a new front sight, that will make my CZ zero in a 410 grain bullet at 50 meters.

Now... From where to where do I measure the height of a front sight?
Do I measure to the bottom of the bead?
Do I measure to the middle of the bead?
Do I measure to the top of the bead ?

And where do I measure from?

My rear sight is a standard V shape which I have used with the bead "lying" on the V, covering the target. So to my recollection, sight height should be measured to the bottom.

Once I have found this out I secondly need to calculate what height I need.

How do I calculate the right heigt of the front sight?

Thanks for any help.

Niels

Brownells has a chart in their catalog for amount of change needed depending on sight spacing

Get a Brownells catalog...pg 233 for height correction chart...pg 234 for calculating sight heights.

You can email them the question and probably get a much better answer within a couple days...with an explaination much better than I can present.

Roughly 0.005" higher blade height equals 1" lower POI per 100m...0.010" more blade height equals 2" lower POI...etc...

Or 0.010" higher blade height equals 1" lower POI per 50m, 0.020" equals 2" lower POI per 50m...etc...

It also depends on the distance between front and rear sights and the original front sight height measurement.

Raise front sight to lower POI...or lower rear sight to lower POI...move rear sight in the direction you want the POI to move or opposite for the front sight.

EXAMPLES...

For 18" distance between front and rear sights, a 2" high POI at 50m, a 0.400" front sight blade measurement, you will need to add roughly 0.020" to the front sight blade height or change to a 0.420" front sight blade height...

For a 20" distance you add 0.022" or 0.422", for a 22 inch distance you add .024" or 0.424".

Front sight blade height is just the dovetailed blade NOT including the ramp.

The easy way...go to the next higher front sight blade and call it good...at 50m you're not talking benchrest groups...or hand it over to your local smith and let him do the calculations...

OR...much Better yet..practice enough to know where to put the bead in the "V" for the different ranges...I don't think you will have time to break out a lazer range finder to get exact ranging.

Thanks. This is good info. I knew I could rely on AR guys to help me out. Thanks a lot.

I need the iron sights set zero for 50 m. I use this gun for Moose/bear hunting, so far with a scope only, but a zero of 50 on the iron sights will give me a back up for the scope and allow me to shoot out to 100m. which I will never need.

Thanks again

Niels

If you already have sights on the gun, I have a formula that tells you how much higher or lower your sight needs to be with no measuring. You shoot the load at the desired range and then:

The (error in inches times the sight radius in inches) divided by the distance to the target in inches

Or you can do it in millimeters, it all depends on how they measure the sights that you are buying

Example 2 inches low at 50 yards with a 20" sight radius would be: (2" X 20") Divided by 1800" equals .022" Since shooting low you will need a .022" lower front sight.