All-Terrain Armored Transport
The All-Terrain Armored Transport (AT-AT) is a quadrupedal armored fighting vehicle used by the Galactic Empire during the galactic civil war.
Design
The AT-AT is a poorly designed vehicle. Among its design problems are vulnerability to being tripped (Which was exploited at the Battle of Hoth), guns that can only fire in the forward arc, and a large target profile. In spite of this, the AT-AT is a formidable vehicle if only due to its sheer size.
The main guns of the AT-AT, assuming that TESB is used as a standard, appear to have an effective range of about 18 KM (the range at which Veers's walker destroyed the rebel shield generator). By comparison, the M1A2 Abrams's M256A1 120 mm smoothbore gun has a lethal range against MBTs using kinetic penetrator rounds of just over 3 KM. In a stand-up fight, the AT-AT could theoretically knock-out the Abrams before the tank crew was even close to being in range to shoot back.
Of course, in the actual canon Star Wars, the AT-AT is not the Imperial analog of a real-life tank and so comparing them is a bit of an apples-to-oranges comparison.
(...And how honest of you to take a statement of mine and deliberately edit it into a new context).