front sight height help

[Brian Dick]

No.4 w/o bayonet fixed, sights set at 200, MPI should be 3" above the point of aim at 100 yards. Zero here first and then make your FS change as necessary for your ammo.

This information is all in the 1955 Infantry Training Pam. I have them available if in need. Everyone who owns and shoots the No.4 should have one.

[ActionYobbo]

Hang on a mo and I will find something;
Try this I typed in the search bar; Calculating 303 foresight height and found this thread at the top have not read it all but it seems close......https://www.google.com/url?q=http://...vzDX11LW1rTOKw

I think the formula you require is written just above the 3rd chart down...

Here I even cut and pasted it so others can benefit from what was written;

To calculate the difference a change in foresight would make at the target in relation to the point of aim use the following formulae (in Inches).

(Range x Difference in Height of blades) divided by sight radius = variation on target

Alternatively to calculate the correct foresight blade to fit to a rifle to achieve zero use the following formulae (in Inches).

(Sight radius x the height of the group MPI -usually 5 shots- above or below the point of aim) divided by range length = the change in height of fore sight needed

those formulas are fantastic. using those formulas I need a -2.5" front sight. work it out to see if I made a mistake I am 15" low at 300

Exactly...or don't you shoot at closer ranges?

the range I shoot at is 300 to 1000. there is a 50 yard range 90 minutes drive form me but its a $100 a year membership
the ranges I shoot at are 25m rimfire of 300 to 1000 fullbore

I'll stick my neck out....

Having measured that 1 click of the No 4 rear sight moves the leaf near enough to .008", by my reckoning you could try a -.045 foresight.

Logic for this is that there are 7 clicks between 600 and 500 on the rear sight, so the sight change required is .056". Each foresight blade increment is .015", so if you came down by .060" I think you would be fairly close.

I too would be interested in how your rifle shoots at the closer ranges, and how the 6 o'clock hold issue enters the picture.

In my own case, I choose to zero (centre hold) at 100 yards; then use a 7 click elevation offset after changing sights for range to allow for the 7 inch distance between aiming mark and centre of bull.

thank you. this is what I was looking for.
I will buy a -.045 front sight and try it

[Maxwell Smart]

Mr E, where does your 6 o'clock hold come into the picture?

When you say that your sights are 100 yards out, is this for a centre hold or 6 o'clock hold?

[22SqnRAE]

Mr E,

I am having similar problems and have had to learn quickly. You have probably already thought of the following suggestions, so bear with me as I'm not insulting your intelligence, research or preparation.

Cinders is bang on with the formulae and every Lee Enfield owner needs a copy of these to understand their rifle. Brian's #11 post is the next excellent part of the equation.

The REME Armourer's Training Pam indicates the tabulated data for zeroing each of the Service Rifles at 25 yards and 100 yards. You've got a problem in being only able to use 300+ yards. OK, here's the suggestion. Like previously mentioned, grab a suitable (big) target like a pistol target and bung it up at 300. Set an aiming mark, shoot three to five 3-shot groups, comfortably, from a fully supported position. Grab the target and measure up the MPI for the groups.

Use measurements by dividing the difference between the MPI (observed) and the MPI (theoretical) and divide by 3 to bring it back to 100 yards and therefore MOA.

From what I have estimated from commercial ammo 174 and 180 gr projectiles, for a 200 yard zero, the MPI at 300 yards will be around -10.5" to -11.5"

With Agent 86's excellent info on the rear sight movements for the No 4, you have enough variables for the equations to determine the required foresight. The exercise is simple linear geometry. Keep all units the same and you can't go wrong.

In summary: sight at 300, reduce to 100 yards numbers (simple triangular ratios) and you then have the measurements to assess changes in accordance with REME Armourer's instructions. There are reproduced in part in the link:

http://www.rifleman.org.uk/PH_Service_sights.htm Scroll down to Zeroing...

[musketjon]

Why not just file down the front sight blade a little? Hand work is cheaper and faster than a blade replacement.
Jon

[muffett.2008]

Great fun filing down sight blades.
I was part of a selection team practicing for an overseas competition.......part of the SMG Team.
Anyway, we had just finished a zeroing practice and a couple of the lads needed to adjust sight height...........next thing we know, the top shot of the team was doing some serious abusing and ranting, seems someone had mistakenly picked up his F1 and was busily engaged in reducing the sight height.........and yes, he didn't make the team.

[CINDERS]

Bet he was doing this Muffett

[Outpost75]

It is very handy to know that two clicks on the elevation knob of the micrometer battlesight, with allowance for backlash in the threads, approximates the next front sight increment!

Bravo Zulu Sir!

[30Three]

"those formulas are fantastic. using those formulas I need a -2.5" front sight. work it out to see if I made a mistake I am 15" low at 300"

I believe you did make a mistake! The formula is good and I've used it many times for rifle and pistol. Saves a lot of time.
Example:
Distance between front blade and rear sight 24"
Error on target 15"
Distance from muzzle to target (300 yards) 300x36=10800"
24x15=360
360 divided by 10800 = 0.033" so 33 thou required if you sight radius is 24".
This is just an example I have not measured my No4 sight radius but I think you can see how we do it. Make sure all figures are in inches or at least the same scale.

[Peter Laidler]

Can you just imagine it........ A rifle company on the range for their annual shoot, a few Armourers and training staff working from the back of a Bedford, working out all these formula for each individual rifleman intermixed with GPMG's, Brens and SMG's. Nope, me neither! We just got on with what we had and were taught. Simple - and worked first time