@johny_baba
regarding the new ARDE carbine and SSSD statement some where, both have mentioned being able to fire both INSAS and NATO rounds, from a technical stand point what does it mean?
in case already discussed, do point me towards that post.
to keep it short,
INSAS ammo has (almost) same dimension as NATO one,
but,
INSAS ammo is "hotter" = propellants used create more powerful blast, gas pressure and subsequent recoil is higher, bullet fired has slightly longer base at bottom (inside the cartridge side) and bullet construction is slightly heavier (in grams)
so INSAS requires a sturdier construction of chamber, barrel specifications too should be altered in accordance to that, and of course gas system has to be strengthened for it
since ARDE Carbine is build on INSAS tech at home, it's obvious for it to follow it, but for an AR design that SSS D is making in name of M72 it has to be further altered to allow proper firing for this ammo,
normal M4 and NATO spec 5.56mm weapons would cycle faster, and subsequent wear-tear of parts inside would also go up when fired with INSAS spec ammo
so both designs are projected as INSAS compatible = they have taken these differences in mind and designed-produced their weaponry accordingly, good thing to have for Indian Armed Forces that has a stockpile of INSAS ammo
sidenote = when very first XM16E1 = M16 rifle faced inner jungles of Vietnam, a thing happened where
=> the rifle was specifically made for improved NG+NC based propellants
=> US Armaments had stockpile of older NG based propellant called "ball powder", they simply thought heh we just gotta use this, who bothered with such minute things, a supposed 'space aged' design would easily tolerate it
=> ball powered ammo, well it worked, but it also left far more carbon residue inside then M16 and when it was a (improved) direct impingement gas system design, it further fouled its receiver side things
=> result = these fouling would line up in its gas tube, gas key and inner gas chamber of bolt carrier, cause gas pressure to go further up, and it would cycle much faster sometimes at 1000-1200 rounds per minute, but parts weren't really made for these high level of pressure and cycling, so it would literally start chipping at here there, bolt would pull on a chambered and fired ammunition case with such a ferocity that it'd literally rip its rim off and cause severe stovepipe-ish jams
=> worst of all, the US grunts there weren't issued with proper lubricants, or even cleaning kits or manuals much so they can keep their firearm clean and going well
=> when complaints became loud enough, they had to do a lot in regarding all these to solve some if not all issues in harsh environment operation with unsuitable ammo and all
hope you get a basic gist with this post
(now don't literally compare INSAS with vietnam era M16, both are totally different weapons with different set of issues, but this point of 'hotter' ammo of INSAS in NATO spec non-INSAS weaponry holds some mattle)
