Copied from indiadefence forum
At first look & touch, The rifle is compact & Light weighted compare to INSAS 1B1 which is in service, The size of the rifle is more or less same as a M4 carbine, This is probably because the barrel is not a 18 inch as its on 1B1 but this Excaluber has a 16inch barrel !, Unlike what i saw previously in defexpos, Excalibur has 18inch barrels, This means Excalibur has variants & the one in my hand was a 16inch barrel one for CQB ops
The rifle Excalibur as seen in the picture is smaller than an AK47/AKM and little longer than TAR-21 of 18inch, It was lighter around 2 kgs and with full loaded 22rnds Magazine its weight is around 2.5kgs, Unlike 1B1 is 3.5kgs full loaded, It was pleasure to hold this Rifle ..
Here the Rifle is in folded butt configuration, To be frank the size in this configuration was lesser than 9mm silenced carbine used in Army , This is perfect and impressive in CQB ops, where fighting is in tight corners ..
Now lets see some details in selector switch, S for semi auto, R for safety and A for automatic, This is not same with 1B1 as 1B1 options have no automatic but Burst, The switch itself is not same as 1B1`s, The Rifle is design for spray and pray like AK which is again for CQB ops, Also the Grip is also not like AK or 1B1`s, Though the Rifle retain similar 1B1`s rail, Trigger and almost all other major important parts for operating the rifle hence no new training for using this rifle..
What makes Excalibur looks different from his brother 1B1 is the over all fore-grip design which extend over gas pipe so does till Cocking handle, The material used is not a cheap plastic as many would call, But was rugged and good hard fiber furniture, Same material is used in Rifle butt, It is important to note the material used on Excalibur is not the same used over Improved 1B1, Excalibur is indeed a improved INSAS over Improved 1B1 INSAS, Unfortunately its not under service ..
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Conclusion : What i learned is that Excalibur has different version itself, Mainly with different barrels and it is design for both Long and Close combat operations, It is light and short compare to 1B1 in service, I was impressed with the fiber quality that Rifle offers compare to 1B1 also the Rifle operation is same as 1B1 hence it does not require new training to handle, Overall its a good design rifle and deserve operational service within Army..
It is also unfortunate that i cannot used this nice Rifle over firing range to know full extend of its capability and preform-ace ..
Cheers !
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Keeping location Private ..
The muzzle climb is primarily due to torque. Yup, the same RxF torque we used to study at 11th standard.
And with any case involving torque, there exist a point of application of force and a point about which the object (in this case the rifle) rotates, both lying in the same plane.
Here in the image above, the black point is the point about which the rifle attempts to rotate, and the blue line indicates the line of action of recoil force due to the bullet leaving the barrel. (The reaction force always acts along the line of action, but in the opposite direction)
As can be seen, there is quite a bit of vertical gap between the point of contact and the line or recoil. As such, a torque is generated about the black mark, which in this arrangement comes to be anticlockwise, resulting in the muzzle climb. If the situation was reversed and the gun barrel was below the point of support (contact), the torque would be clockwise, i.e. downward muzzle movement.
However, with the new stock, as can be seen in the image below, the line of action of recoil passes nearly through the point of contact. This implies that there will be nearly no muzzle climb. In effect, the shoulder will be in line with the barrel when the recoil comes, unlike in case of Ak-47, where the rifle barrel is quite above the shoulder. (
This is even better in case of certain other rifles.)
Of course many may wonder why I have positioned the support point above where I positioned it on the AK-47, but this is actually the location of centre of pressure. In the case of AK-47, the line of action passes above the stock at the plane of contact, as such, this has a different effect on center of pressure. The forces are evenly distributed across the cross section of the stock end in the case of Ak-47.
While in case of the Excalibur, the line of action of recoil passes through the top of the stock at the plane of contact, meaning the most of the recoil force is concentrated at that point, thus the difference.
Also, the choice of polymer material has another set of advantages.
The most important being that polymer is a much better dampener than wood or iron for energy passing through the same thickness of material. As such, shoulder fatigue sets in much later as the shoulder is protected to a greater degree from the energy of recoil.