What is stopping power?
Wiki states:
Stopping power is a colloquial term used to describe the ability of a firearm or other weapon to cause a penetrating ballistic injury to a target, human or animal, sufficient to incapacitate the target where it stands
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The term is not a euphemism for lethality. It refers only to a weapon's ability to incapacitate quickly, regardless of whether death ultimately ensues. Some theories of stopping power involve concepts such as "energy transfer" and "hydrostatic shock," although there is disagreement regarding the importance of these effects.
Stopping power is related to the physical properties of the bullet and the effect it has on its target, but the issue is complicated and not easily studied. Critics contend that the importance of "one-shot stop" statistics is overstated, pointing out that most gun encounters do not involve a "shoot once and see how the target reacts" situation.
Stopping is usually caused not by the force of the bullet (especially in the case of handgun and rifle bullets), but by the damaging effects of the bullet, which are typically a loss of blood, and with it, blood pressure.
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The issue is does the weapon incapacitates the enemy? If it does, then it is fine.
The accepted range by which a rifle is to incapacitate the enemy is 300 yds. For doing so at greater ranges, there are other weapons like the LMG, MMG, HMG.
Now if the rifle is to do the task of an HMG, then why have a rifle? One has to understand internal, external and terminal ballistics to understand the behaviour of a bullet and the bullet's design and 'powder' also plays a role in what is known as the 'stopping power'. The wound ballistics are also pertinent.
How does one stop the enemy?
It is done in a graduated manner. HMGs at greater distances and then the LMG and then the rifle and then the Sten and pistol for CQB. In addition area weapons like artillery and mortars of various calibres are used. Rifles are used in the intermediate range between the LMG and the CQB weapons.
In my rather long service, I have observed the change from WWII weapons to the modern ones. In so far as the calibre etc are concerned, we have been enamoured by NATO and US theories. The fact that the US military industry nexus is a powerful one and hence they are always innovating or putting forward theories that encourage a change in weaponry so that they can engine their companies. Their strong advocating of 5.56 as the nirvana caused the whole world to change to 5.56 and now they are touting a medium calibre between the 5.56 and 7.62 with the accompanying marvels that it will so cause.
It must be understood that the IA follows the British concept of holding fire till the 'whites of the eyes' of the enemy can be seen. The Americans on the other hand, feel comfortable engaging at long range with automatic fire. The luxury of expending ammunition is not a hindrance to them given their economy and facilities for replenishment. IA cannot afford that luxury for a variety of reasons. In the mountains for instance, ammunition is hauled up on man or mules and not by helicopters since we do not have the multitude of aircraft to sanitise the area to permit helicopter insertion of munitions and other warlike materiel. In mobile battles, because of the lack of excessive airpower to sanitise the area, the soldier has to rely on what is on manpack and in the F and A ech and then await the replenishment from the rear. Therefore, the US mode of operating is different from ours.
A study of the ISAF operations would indicate their mode of operating. In comparison, I daresay we have done better. There are good reasons for that too that space constraints discussion.
One should also not be enamoured by western equipment. They are cosmetically alluring, but then in Iraq, the US soldiers preferred to use the AK 47 to the US rifles. Therefore, looks is not the answer. Performance in various conditions is!
Accuracy is dependent on the skill of the firer and how comfortable with the weapon.
Automatics are used by the Americans only because of this reason - to overcome poor marksmanship. If one fires a whole lot of ammunition, then is axiomatic at least some will hit and do the job!
In CI and defence, one does not fire at long ranges.