The Thunderjet was originally proposed to have the P-47 armament of eight .50 caliber machine guns or six of the new and as yet to be proven .60 caliber machine guns. When the original design based on the P-47 modification was abdicated, the replacement design originally specified four .50 caliber guns; this was later increased to six .50s. When the A-models were equiped, the guns were Browing M2 .50 caliber guns; four in the upper-nose gun bay, and one each near the wing roots; rate of fire was 800 rounds per minute. B-models were manufactured with, and A-models were retrofitted with, Browing M3 .50 machine guns; rate of fire was 1,200 rounds per minute.
B-models had retractable underwing pylons to carry eight five-inch HVAR (High Velocity Aircraft Rockets).