You and your logics are epic man........
Accuracy with high power bullet is okay. But accuracy with less powerful bullet is not desirable at the cost of fire rate. In anyway, German infantry was better than British infantry. Germans having MG 42, MG 34 and supported by MP 40 and Kar 98K was better than Brain Gun Centric British troops armed with Lee Enfield and Sten Gun.
And best system Americans had, their M1 Gerand Semi-automatic rifles fared better than Bolt Action rifle armed other countries. In WW2 era, semi-automatic rifle and bolt action rifle's difference can be considered today's difference between semi-automatic rifle and full automatic rifle. Americans fared better with almost every soldier of them being equipped with M1 Gerand. Later Soviets came with arming entire divisions with sub machine guns and Germans with their STG 44. British themselves abandoned accuracy when they retired Bren Gun and adopted full automatic rifles.
Its during the WWII era which you mentioned, the concept of Assault rifle is born. Before that either its the battle rifle or MGs. Germans were the first to use 9mm pistol bullet in there very first version of assault rifle, the Grease Gun. Why you think they adopted AK47 after WWII instead of their StG44?
Bullets like 7.62 are not accurate enough. The first requisite and idea of Assault rifle was :
1-- It should be one man portable
2-- It should have the firing volume of a Machine gun
3-- It should have the range and accuracy of a rifle.
Many rounds had been tried to meet all the requirements and each and every round thus seem to have one problem or another. Rounds like 7.62 or 7.92 were not fit enough to fire accurately and volume of it means reduced life span of the overall weapon system. So to overcome all of these, the standard of 5.45 had been accepted after WWII.
Regarding stopping power, let me quote something from Wiki.
Despite complaints that the 5.56×45mm NATO round lacks stopping power, others contend that animal studies of the wounding effects of the 5.56×45mm NATO round versus the 7.62×39mm have found that the 5.56×45mm NATO round is more damaging, due to the post-impact behavior of the 5.56 mm projectile resulting in greater cavitation of soft tissues
The problem which arose regarding the stopping power of 5.45 is attributed mainly to shorter barrel of modern ARs. The original barrel of INSAS B1 was 18 inch which was later reduced to 16 inch in later version of 1B1. Now for a more damaging shot by 5.56 studies shows that you need a 20 inch barrel as that of old M16.
So in short, when it comes to short range, 7.62 is good with its massive punch, but when it comes to accuracy at longer range like 300 mtr + 5.56 is better.
That's why I said, a soldier in Siachen and what they prefer should not be necessarily doctrine of entire IA. In Siachen Soldiers armed with INSAS are given 22 round magazines which is acceptable as you said. But then why even a BSF Jawan patrolling Bangladesh border is also given 22 round magazine?
I will prefer to have the AK instead. More ammunition I have, the better.
AKs are provided in all the troublesome area for patrolling purpose as well as COIN. As far as weight goes, have a look at this chart.
Rifle Cartridge Cartridge weight Weight of loaded magazine Max. 10 kilogram ammo. load
M14 (1959) 7.62×51mm 393 gr (25.4 g) 20 rd mag @ 0.68 kg 14 mags @ 9.52 kg for 280 rds
M16 (1962) 5.56×45mm 183 gr (11.8 g) 20 rd mag @ 0.3 kg 33 mags @ 9.9 kg for 660 rds
AK-47 (1949) 7.62×39mm 252 gr (16.3 g) 30 rd mag @ 0.92 kg[8] 10 mags @ 9.2 kg for 300 rds
AKM (1957) 7.62×39mm 252 gr (16.3 g) 30 rd mag @ 0.82 kg[9] 12 mags @ 9.8 kg for 360 rds
So which do you think you would prefer? 360 rounds of AK mag with 30 round per mag or 660 round of 5.56 with 20 round per magazine?
I do understand it. Yet weight difference between INSAS 1N and INSAS LMG is not so. INSAS LMG no where weighs like M 240 which has over 12 kg weight.
Again you are mixing things over here. M240 is designed for 7.62 mm and INSAS LMG is designed for 5.56. Any gun designed for 7.62 round would be heavier then anything for 5.56 mm.
M 16 Rifle originally had no problem, it was problem with cartridge. INSAS 1B's technical problems can be compared to it. But M16A1 did not suffer from faulty doctrine.
M16 rifle originally had no problem? Let me quote one Marine Corps Rifleman from Vietnam.
We left with 72 men in our platoon and came back with 19, Believe it or not, you know what killed most of us? Our own rifle. Practically every one of our dead was found with his (M16) torn down next to him where he had been trying to fix it.
— Marine Corps Rifleman, Vietnam.
As far as any doctrine is concerned, the keep on evolving. There is nothing like fool proof or faulty doctrine. Doctrine are subjected to be changed and armies world over do learn from their mistakes.