Muzzle Reference System

[Jartsev]

Stupid question: how to operate the MRS used on modern western tanks like M1 and Leo2?

Edited October 14, 2006 by Jartsev

[Der_Opa]

Stupid question: how to operate the MRS used on modern western tanks like M1 and Leo2?

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English terms are not my strongest side, but I assume you mean how you adjust for barrel drop using the muzzle reference mirror? In the Leo2, you need to be in Stab EIN(stabilisation engaged), you then flip on a "field adjustment"-switch, and the gun will move into the correct position.(50 mils elevation) This will cause the GPS to orient itself towards the muzzle reference. If you look into your sight now, you'll notice that it's pointed directly towards the muzzle reference.

 

You then attach a lamp to one of your oculars, and observe through the other one. This will send light through the GPS, which will hit the mirror in the muzzle reference, and be reflected back. This will create a shadow of the reticle, since the reticle will be blocking some of the light. If the barrel is properly aligned with the sight, that shadow will coincide with the reticle, that is; you will only see the reticle. If you see two reticles(the real one, and the shadow), you use 2 knobs to adjust the sight until you just see one reticle. One reticle=sight is properly aligned, 2 reticles=sight is not properly aligned to the gun.

 

Edit: Corrected from "gun is properly aligned" to "sight is properly aligned"

Edited October 14, 2006 by Der_Opa

[Jartsev]

English terms are not my strongest side, but I assume you mean how you adjust for barrel drop using the muzzle reference mirror? In the Leo2, you need to be in Stab EIN(stabilisation engaged), you then flip on a "field adjustment"-switch, and the gun will move into the correct position.(50 mils elevation) This will cause the GPS to orient itself towards the muzzle reference. If you look into your sight now, you'll notice that it's pointed directly towards the muzzle reference.

 

You then attach a lamp to one of your oculars, and observe through the other one. This will send light through the GPS, which will hit the mirror in the muzzle reference, and be reflected back. This will create a shadow of the reticle, since the reticle will be blocking some of the light. If the barrel is properly aligned with the sight, that shadow will coincide with the reticle, that is; you will only see the reticle. If you see two reticles(the real one, and the shadow), you use 2 knobs to adjust the sight until you just see one reticle. One reticle=gun is properly aligned, 2 reticles=gun is not properly aligned to the sight.

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Wonderfull! Thanks!

[Cavalier]

If you see two reticles(the real one, and the shadow), you use 2 knobs to adjust the sight until you just see one reticle. One reticle=gun is properly aligned, 2 reticles=gun is not properly

If the reticle inner circles (real and shadow) are coincident, secant or tangent it's acceptable and it's not necesary any adjustment.

 

The gunner should check the alignement every four to five shots, if it's tactically possible.

[Der_Opa]

If the reticle inner circles (real and shadow) are coincident, secant or tangent it's acceptable and it's not necesary any adjustment.

 

The gunner should check the alignement every four to five shots, if it's tactically possible.

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If the deviation is less than 0,25 mil(iow, tangent or less), it is not necessary to perform a new boreline adjustment. You can still adjust according to the muzzle reference system. You just don't have to use the boreline-optics.(Don't know the english term for this, but it's essentially a "sight" placed into the gun during sight adjustments)

[Cavalier]

Ops, you are right.

 

You should correct the deviation and place the shadow over the true reticle every time.

 

When the gun is cold (before firing) a deviation more than 0.25mil means it is necesary to boresight (boreline adjustment?).

When the gun is hot and the deviation is more than 0.25 you can still use the MRS.

Edited October 14, 2006 by Cavalier

[Guest JamesG123]

The M1 is functionally different only in that it has a self-illuminating MRS, so all the gunner has to do is put it in MRS mode, toggle the reticle to the center of the MRS' crosshairs, throw it out into normal mode and be good to go for another 5 or so rounds or a gross change in air/ground temp.

 

How sharp is the Leo's "matching reticle" MRS image? I always found the MRS on the M1 to be "fuzzy" and hard to get aligned right.

[Der_Opa]

How sharp is the Leo's "matching reticle" MRS image?  I always found the MRS on the M1 to be "fuzzy" and hard to get aligned right.

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It's not noticably different from the real reticle. Not a problem to align.

[Stephan]

One addition, on the Leopard 2A5 and upwards, the illumination has been integrated into the optics, the additional light is not necessary any more (which is a sad thing, as it made for a great reading light...).

[AlexW]

One addition, on the Leopard 2A5 and upwards, the illumination has been integrated into the optics, the additional light is not necessary any more (which is a sad thing, as it made for a great reading light...).

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If the MRS is not aligned properly, how do you make the adjustment on Leo2 and M1?

Are there any MBTs with auto MRS adjustment? Leclerc perhaps?

[Guest JamesG123]

On boresighting you get the baseline MRS "boresight" or alignment. Then as the boresight goes off due to heat expansion of the tube, and shock from firing, adjusting the MRS brings the sights to where the tube is.

 

The only system I have heard of that has an automatic MRS update was the South African T-72 with those cludgy sights welded onto the external armor. That thing probably needed a constant alignment check in order to stay accurate.

[Froggy]

If the MRS is not aligned properly, how do you make the adjustment on Leo2 and M1?

Are there any MBTs with auto MRS adjustment? Leclerc perhaps?

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The MRS adjustment is semi-automatic on the Leclerc.

When you make a boresighting, the system memorize the position of the gunner sight miror with the MRS.

On the field, TC just command a field boresighting, and the system put the miror back to the last manual boresighting position. It take less than 10s.

Manual boresighting is needed only if the gunner sight has been removed, or changed.

There was an automatic bend measurer, using a laser, to correct static and dynamic bend, but it has been removed.

Edited October 16, 2006 by Froggy

[Chris J]

The MRS adjustment is semi-automatic on the Leclerc.

When you make a boresighting, the system memorize the position of the gunner sight miror with the MRS.

On the field, TC just command a field boresighting, and the system put the miror back to the last manual boresighting position. It take less than 10s.

Manual boresighting is needed only if the gunner sight has been removed, or changed.

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What you describe is not auto MRS. What AlexW is asking about is a system which performs the MRS adjustment transparently to the Gunner, ie with no intervention. The main issue with this is when to do it, for maximum accuracy it has to happen just prior to the round leaving the barrel. Hence a dynamic MRS, one that constantly measures barrel deformation, is more desireable as there isn't time to make the measurement after the trigger is pulled and before the round is initialised, this way at least you have a recent measure of deformation. Dynamic MRS isn't viable with implementations using the Gunner's sight mirror though as naturally this has more important work to do. Hence more optics, more cost, uncommon etc....

 

 

There was an automatic bend measurer, using a laser, to correct static and dynamic bend, but it has been removed.

380405[/snapback]

 

Once saw the data from one of these systems, out of thoroughness the barrel was also instrumented with (comparitively) very low cost accelerometers for the investigation, the data from both corellated brilliantly, so the point of the DMRS was.............