 It was decided new P-51Bs (NA-102s) would continue with the same armament and ammunition load of the P-51A, while the bomb rack/external drop tank installation was adapted from the A-36 Apache; the racks were rated to carry up to of ordnance and were also piped for drop tanks.The machine guns were aimed using the electrically illuminated N-3B reflector sight fitted with an A-1 head assembly which allowed it to be used as a gun or bomb sight through varying the angle of the reflector glass.Pilots were also given the option of having ring and bead sights mounted on the top engine cowling formers.