It is said that Brahmastra is released by a mantra derived from gayatri mantram.
Some also believe that Gayatri mantram itself is used to release Brahmastra.
Then a question arises- why can't everyone who knows Gayatri mantra release Brahmastra?
I'm a twice born (Brahmin) and since the day of my thread ceremony (Upanayanam), as a tradition i should chant Gayatri mantram daily, and i do. So can i release Brahmastra? Definitely NOT!! Then what's the difernce between me and Dronacharya (another Brahmin) who could release Brahastra? The answer being a simple fact which is detailed below:-
All Mantras have great potency.One has to gain siddhi on a particular mantra before it works miracles for him. Now what is siddhi? Every mantra needs a particular no. of repeatation after which it becomes 'Siddh'. Siddhi is nothing but when a sadhaka chants with full concentration a particular mantra for a particular no. of times (no. varies and is either in thousands or lakhs or crores for each type), it gives him siddhi in that. Siddhi is nothing but that particular person himself becomes charged with that mighty energy.
In the case of Brahmastra, when a person is trained how to chant Gayatri mantra for Missile purpose, a person has to gain siddhi on it, and when he acquires it, he gets energized. With that energy when he releases even a grass blade by chanting that Gayatri mantra it turns into Brahma Missille due to his own charged energy and the missile inturn derives it's power from Lord Brahma.
This siddhi concept is not only limited to Astras, but it's all about a human being turning divine...We have seen many examples in our scriptures. Kapila muni had destroyed 1000 sons of Sagar just within a moment. Did he use any weapon? NO..he used his enerygy. How did he gain his energy? He should definitely have worked on some divine mantra and got energized himself.
We have also observed in the scriptures that sages usually refrain from giving curse. Only when there is no way they give curse. Why? Why can't they freely donate curses to anyone whom they see as sinners?
Reason is, when a siddh yogi (Energized human body) gives a curse, it decreases his aura (Teja/Energy) to a large extent, since curse also works by deriving enerygy from the Yogi's energy pool. However it wastes the energy to a great extent. so, usually saints refrain from wasting the energy since they always believe it should be used constructively. The same thing holds good for releasing the Brahmastra kind of Maha Weapons, sinc ethey also consume lot of energy and hence should be used when there is no other go.
Now coming back to Brahmastra again:-
Brahmastra is released by Chanting Gayatri in a specific manner, the syllable sounds and pitch may differ from normally what we chant during our puja.
So, a question arises, what's the diference between those two chants? Let me tell you that Sonic energy (Sound) is extremely powerful, since it's afterall energy!!
Any noise made at a particular frequency can destroy objects. We have examples where sound made in a particular high pitch destroys glass (metals and other objects as well).
In Stephen Knapp’s article “Frequencies that can kill, heal and transcend” he states, “The science of vibrations and frequencies and how they effect people is something that has been around for thousands of years. We can still find evidence of this in the ancient Vedic texts of India. These explain not only the results of using the frequencies of words and mantras, but also supply instructions in some cases. The sages of ancient India used it to produce various results in the rituals they performed, and from the mantras they would recite. If the mantras were recited in particular ways, certain amazing results would take place, including changing the weather, producing certain types of living beings, or even palaces. Others used it to produce weapons, like the Brahmashtra weapon, which was equal to the modern nuclear bombs. Specific mantras could be attached to arrows, with the sound causing powerful explosions when the arrow reached its target. Others used the science of vibrations to bring their consciousness to higher levels of perception, or to enter spiritual reality.” (This paragraph referred from here).
Now another question arises; if that is the case for Brahmastra, when a person chants gayatri at a very shrill sound, wouldn't that effect the listeners?
Well, it's not the sound which we hear. There are two types of sounds, before describing them let's know what is sound.
Sound is referred to as the “Nada Brahma” or the divine sound, that is to say, in abstraction too there is a connection with the divine. There are two types of sound: un-struck/un-heard sound and struck/heard sound. Un-struck sound is a vibration of ether, the upper or purer air near the celestial realm. The enlightened yogis seek the unstruck sound called “Anaahata Nada”, and only they can hear it. The struck sound or “Aahata Nada”, is the vibration of air in the lower atmosphere closer to the earth. It is any sound that we hear in nature or man-made sounds, musical, and non-musical. So to release Brahmastra it's the Anahata sound which is used to chant Gayatri and not the normal Aahata sound which we use for puja.
Also, since it's a person's divine energy which is used to propel the Brahma missile which in turn derives further energy from Lord Brahma, the destruction effect varies. It's not like if Drona releases Brahmastra, whatever effect/destruction it caused, would be the same if Lord Brahma himself releases the astra. In former case destruction would be massive, but in latter case it would be an annihilation in an astronomical range...!!
The sum and substance of this article is- Gayatri Mantra chanted in normal way can have healing and good benefits on a human, but when particularly chanted in a different/varying pitch (Anahata Sound), can turn a Darbha (Grass Blade) into a Brahmastra! Only the Guru teaches the right desciple the way to invoke Gayatri into running a Brahma missile. Otherwise any tom dick and harry who knows Gayatri mantra could have played with Brahmastra. Thank God for not disclosing the key to everyone, otherwise the world would have become a grave yard long back!!
Brahmastra in Metaphysical plane:-
Till now we have discussed about Brahmastra in it's real and true form. But let's correlate this to our inner self and see what ebenfit we achieve if we release the Brahmastra present in our own body.
There are two planes,
In physical plane if we understand Brahmastra then it's a weapon of mass destruction. We have discussed this above. In Meta-Physical plane we can assume Brahmastra as the Kundalini Serpent power. This Brahmastra is located within the 'Mooladhara Chakra/Base shell' of our body situated near the Anus.
When a sadhaka (Warrior) meditates and raises his Kundalini, his kundalini (Read Brahmastra here in this context), derives energy from his base chakra (Mooladhara) and propels upwards. On its way, it penetrates through 5 other chakras deriving energies from them at every stage. Finally it hits the target-Crown chakra (Sahasrara) and explodes there with a brilliance. That explosion annihilates all "Illusion/Maya", and leaves the sadhaka with the debris called as "Aham Brahmasmi" feeling.
So, everyone should yearn for pocessing and releasing one's inner Brahmastra but the Brahmastra in physical world should always be in the hands of right people!