My guess is the M1917 Browning machine gun in 30/06
Factory, I'd probably say the 500 Magnum
Other than a toy gun or water gun, the next most powerful one a citizen can have without a permit is a "B.B. gun".
The IS-2 and IS-3 "Josef Stalin". They boasted a 122mm main gun, and remained the most powerful tanks in the world for almost 20 years after the end of the war.
Not even close. There are several more powerful handgun cartridges, not counting the single shot pistols that use rifle cartridges. While Dirty Harry may have proclaimed it to be "The most powerful handgun in the world"- it is not.
50 cal. machine gun. i don't know who decided to use it.
577 T Rex
star cannon
The magnum .55 is the most powerful, but some Desert Eagle has the highest calibre bullet.
light machine gun is the m249 a medium machine gun is the m240 and the heavy machine gun is the browning m2 50. cal machine gun
10 gauge shotgun
Probably the siege gun.
It is the dragon destroyer.