In Alma 43:18 it says that Moroni's people were armed "with all manner of weapons of war." According to Hunter and Ferguson, when the Tultecas [an ancient Mesoamerican people] fought . . . they used long lances, and others which were thrown, and clubs garnished with iron. They wore morions and helmets of brass and gold, and some used the rodelas, particularly those who had clubs. [Milton R. Hunter and Thomas S. Ferguson, Ancient America and the Book of Mormon, pp. 274-275]
“His Moroni's People Were Armed with All Manner of Weapons of War”
According to Daniel Ludlow, one should notice the new and surprising military strategy and techniques used by Moroni in this military campaign. Moroni prepared his people with "all manner of weapons of war" (Alma 43:18), with breast plates, arm-shields, thick clothing, and shields to protect their heads (Alma 43:19). Also he fortified the Nephite cities by having the people cast up "heaps of earth round about all the cities . . . and upon the top of these ridges of earth he caused that there should be timbers . . . built up to the height of a man . . . and he caused that upon these works of timbers there should be a frame of pickets built . . . and they were strong and high. And he caused towers to be erected that overlooked those works of pickets, and he caused places of security to be built upon those towers" (Alma 50:1-4). In actual battle, Moroni often used decoy and encircling tactics to confuse and defeat the enemy (Alma 43:27-35).
Moroni may have obtained some of his new ideas on warfare from Mosiah's translation of the 24 Gold Plates of Ether which contained an account of the wars and contentions of the people of Jared (see Alma 37:29). If so, this may have given him an advantage over the Lamanites because they did not have access to this record. [Daniel H. Ludlow, A Companion to Your Study of the Book of Mormon, pp. 231-232]