Most Aztec arms had been used by earlier groups, but additional ones included a new projectile weapon (bows and arrows) and a new shock weapon (broadswords). The main Aztec projectile weapons were atlatls, bows, and slings. Late Postclassic atlatls had almost 60 percent more thrust than hand-thrown spears, but their effective range was no more than sixty meters. Made of wood and approximately .6 meters long, atlatls had a central groove along which the dart was laid abutted by a hook at the end, and typically had fingerholes, loops, or pegs about a third of the way up the handle. The darts were made of oak and frequently had feathered butts and a variety of points—fire-hardened, obsidian, fishbone, copper, or flint—although barbed stone points were used in combat. The darts were apparently carried loose in the hand rather than in a quiver.

Slings made of maguey fiber were also used, not with randomly selected rocks, but with hand-shaped, spherical stones, and had a probable range of several hundred meters. The Aztecs used simple, rather than compound, bows with sinew or hide bowstrings, measuring up to 1.5 meters in length. War arrows had the same variety of points at atlatl darts and were carried in quivers holding as many as twenty arrows. Poisoned arrows were not used in Mesoamerica, although fire arrows were. Aztec war arrows of standardized sizes were made of straightened reeds bound with maguey fiber to prevent splitting, then fletched, and had obsidian points glued and tied to them; their range was probably 90 to 180 meters.

The main Aztec shock weapons were thrusting spears, clubs, and broadswords. Thrusting spears were 1.8 to 2.2 meters long, with a third of their length dedicated to a cutting surface made of close-set obsidian blades securely glued into grooves. Although significantly less important, several wooden clubs were also used, some plain and others with a variety of stone blades and wooden knobs. Knives were used as well, but in a decidedly secondary role, and axes appear to have functioned solely as execution devices.

An important innovation in Aztec weaponry was the oak broadsword, which was a little over a meter long with close-set obsidian blades glued into grooves on either side. Broadswords often had thongs through which the soldier could put his hand to secure the weapon during battle. Broadswords were a post-Toltec innovation and also post-date the introduction of bows and arrows. The shift from short sword to broadsword eliminated the former’s crushing role entirely but otherwise was probably a natural evolution toward greater size. However, the introduction of archery may also have played a part in this shift; they emphasized the rapid closing of combatants to minimize the effects of the arrow barrage and simultaneously required a more effect close-in weapon, in that both sides sough to establish and maintain close contact to minimize the effect of projectiles.