The length marked in red line for the gun plate is 1140 mm.
If we measure the gun plate's width on the screen it is 54mm on scale.
The thick blue dotted lines or 7 mm distance away from the edge of the gun plate on both sides(if we measure it with scale on the screen)
So a total of 14 mm extra on both sides.
So 54 +14 mm =68 mm is the distance enclosed between the thick blue dotted lines.
Since the 1140 mm gun plate occupies 54 mm scale length on the screen,
The distance between the TWO thick blue dotted lines should be 1440 mm to occupy 68 mm width on screen.
The distance between the TWO thick blue dotted lines is the marked as green carpeted area whose width is 1400mm
The two thick blue dotted lines (picture on the top)on the turret front view photo are 1440 mm apart is my estimate.
It encloses the green carpeted area.
The thick blue dotted line (the green carpeted area's right and left border lines )reaches right at the center of the two crew hatch holes.
So each crew hatch hole is located 720 mm away from the center line(drawn along the length of the gun) of the gun barrel.
But if you see the photo of the Tank commander's seat from the top of crew hatch opening ,
FROM the picture posted below ,it is quite evident that the right hand side edge of the commander's seat finishes well before the center of the crew hatch circle, because you can see the opening for the crew hatch well right of the Tc seat.
the position of the vision block is marked well right of where it should have been near the crew center.
because the TC is almost inline with the gunner not sitting besides him to his right .
Most of his body is enclosed within the the green carpeted area's right and left border lines
There is an elbow room of close to 200 (at the max )mm available for the TC from the outer right hand side edge of the Tc's seat to the inner side wall of the crew compartment.
So the inside wall of the crew compartment is 920 mm away from the turret center line.
The width of the arjun hull is 3200 mm as per the pics posted here.So from the centerline of the turret outter wall is 1600 mm away .
So 1600-920=680 mm space is available for TURRET SIDE armor till the crew hatch from the turret front.
A margin of error of about 100 mm should be factored in this calculation because of the rough estimation .
After the crew hatch center ,storage boxes start which will deduct 200 mm from this space for armor.
So it must be 460 mm along the storage boxes.
But this deduction for storage boxes may be wrong because after the elbow room besides the Tank commander the inner side wall of the turret curves inside negating any reduction of armor besides the storage boxes.
Any clarification on these calculation can be debated.
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The red box scribbled(vision block i suppose) is actually not in front of the Tc's seat,.the position of the vision block is marked well right of where it should have been near the crew center to justify all the wrong estimates for frontal and side armor is my guess.
Actually the vision block or the red scribbled box is situated between the the green carpeted area's right and left border lines
that is the reason why the crew hole is cut off in the 3d illustration posted by DEJAWOLF.
What is right infront of the TC's seat is the big white display panel ,
(Outside the the green carpeted area)
which is just 500 mm before his face(estimation based on the length of his arm)
Since the inside hull compartment is not an exact rectangular cubicle,
it seems to be right in front of the Tc's seat because of parallax error.
So this red scribbled box is not behind the cutaway for main sight on the turret front.
The cutaway for gunner's main sight is outside the the green carpeted area ,
some where between the cutaway and the turret center line.
The distance between the red scribbled vision block box and the big white display panel is roughly equivalent to the depth of the cutaway for the sight on the turret front.
Since the inside hull compartment is not an exact rectangular cubicle , we have no acceptable way of knowing where the crew compartment wall starts behind the big white display.
So in theory at least nothing prevents arjun turret from having the same level of protection behind the cutaway for main gunner's sight and behind the gun mantlet as KUNAL said.
But the ammo storage sidewall is still further inside of the side wall as obvious from this picture.
So it can have as much possible armor thickness as desired by the design team is my contention.
So a direct hit on it will be quite impossible.
it is this picture posted on this thread from which I derived 3200 mm width of arjun turret to base my calculation for side turret armor,which all the contesting 3Dmodelists should be aware of .
the supposed vision block (scribbled in the red )is not right behind the gunner's main sight is my view.
The big white display box must be the one behind the sight .
