front sight heights

[ActionYobbo]

I am trying to work out what height front sight I need for my Mk2 BREN.
I currently have a sight thats marked JI 34 or upside down 43. I have the rear set to 650 to hit at 400. how much shorter do I need to go?

Information

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[Peter Laidler]

Better if you tell us where the SHOTS FALL when your sights are set to the ACTUAL RANGE you're shooting at. Don't forget that these sights are calibrated for Mk7 ball ammo so unless you are shooting that, our calculations will be as accurate as your sights!

[ActionYobbo]

thanks for not being too harsh on me
is there set distance to shoot at to work out the front sight height. I assume I would shoot and then measure the distance from point of aim to point of impact but at what distance should I do this and then how do I work out what height sight to buy.

thanks

[Peter Laidler]

From memory after having zeroed a zillion of them, zeroed in at 25yards, change lever set to R, sights set to 200 7 shots, two warmers into the bank and 5 accurate shots onto the target. The MPI of the group must be 1" to the right of PoA. 4 of the 5 shots to be within a 1.5" x 1.5" and in any case the 5th shot, if applicable, must be cutting the line of the box

I'm sura all this has been written here before.........

8 sizes of foresight from .25" to .46 increasing in .030" increments. I change of foresight blade = 1" at 25 yards

BETTER to zero in at 100 yards. Sights set to 200, all 5 shots to be within or cutting the line of a 6" x 6" rectangle 1" to R of PoA

[Kev G]

Hope this helps ?

ATB Kevin

[ActionYobbo]

thank you Kev. thats exactly what I needed

[Peter Laidler]

Strange those zeroing instructions Kev....... Because the MPI must ALWAYS be 1" to the right of the PoA and it makes no mention of this. If the MPI is at the PoA at, say 100 yards (see info in thread 5) then that is the crossover point of the bullets as they cross the line of sight. The accumulative error will increase greatly as the range increases. I would suggest that the 1972 EMER is the one I'd follow. In short, the MPI MUST always be 1" to the right of the PoA

I realise that this doesn't answer the Q re height of sights but the adjustment is detailed in thread 2. And that is using NATO MK7 ball

[scoobsean]

Strange those zeroing instructions Kev....... Because the MPI must ALWAYS be 1" to the right of the PoA and it makes no mention of this. If the MPI is at the PoA at, say 100 yards (see info in thread 5) then that is the crossover point of the bullets as they cross the line of sight. The accumulative error will increase greatly as the range increases. I would suggest that the 1972 EMER is the one I'd follow. In short, the MPI MUST always be 1" to the right of the PoA

I realise that this doesn't answer the Q re height of sights but the adjustment is detailed in thread 2. And that is using NATO MK7 ball

I only ever shoot at a range that has a 100 yard line. I set my poi and poa to be the same at 100 yards because I only ever shoot at that distance. I bought a spare blade and had to grind most of the right side of the block off to get it to drift far enough over. The sight picture is a bit weird but it works for me

[ActionYobbo]

I always set mine dead on at 400 yards for a 6 0'clock hold on a 6" circle. I use the dot the I method and once I have the sights regulated for 400 the other ranges seem to work. funny thing is my first bren was dead on at 400 from day 1 but me new one is way low but windage is close with the front sight centered

[Peter Laidler]

Your zeroing theory is based on fuzzy logic scooby and Mr E. The mechanical centreline of the Bren barrel is 1" to the RIGHT of the optical axis of the sights. Optical axis always travel in straight lines - as is the mechanical axis of the bore of the Bren......, that is the vertical path of the bullet too.... VERTICAL don't forget.

If the optical line of sight converges with the mechanical axis of the bore at a distance of, say, 100 or 200 yards, then at 400 yards you won't even be hitting the target. Take it from me, based on my limited experience with Brens and optro/mechanical axis! Zero in properly using the tried and trusted EMER formula. It works reasonably well for the British, Australian, Canadian, New Zealand, South African, Indian and 30 or so other user nations for 60+ years now.

Frustrating or what.........