For conventional artillery, as of 2013 the Soviet 2S7M Mialka is the most powerful artillery weapon. It is so powerful that troops working near it when it is fired may be incapacitated.
As there is not much information on Atomic artillery, our main contender is probably the Davy Crockett recoilless gun. It fired a 51 pound nuclear warhead about 2.8 km. As this was well within the danger range of the weapon so it was made as a weapon of last resort and intended to be deployed in Germany to stop the advance of the USSR. An interesting note is that the last test at the Nevada test range was the Davy Crockett.
The labor union's most powerful weapon is the strike.
No :/ Tanks, artillery and fighter planes could all top both the firepower and Anti-Tank/Infantry capabilities of this weapon. :P
Massed artillery.
the most powerful weapon is the lost katana it is +110
the most powerful weapon is the supernova lvl 99. that is the mega version of the harbinger
The weapon of the King of the Gods, Zeus, had to be the most powerful. Otherwise, he would be overthrown by the other gods. Thus, it was his thunderbolt that was the most frightening weapon.
a nuke
canyon
Most historians have come to the conclusion that artillery did not rank high on the list of military tools available to winning a battle. Artillery, however, would seem to be a powerful weapon to use to win a battle.At the Battle of Gettysburg, commanding General Meade had an ample amount of artillery batteries. His 372 pieces of artillery was supported by 8,000 men.
the cannons
A thermonuclear warhead
power and the government