The F-5 series of aircraft comes armed with two 20mm, M-39 cannons, each with 280 rounds of ammunition. The U.S. Air Force and U.S. Navy both used the F-5 in a training role, with different paint jobs and tactics to simulate enemy aircraft in air-to-air combat training.
Master Models has come up with brass replacement gun barrels and a turned brass pitot probe for the nose. Four parts are included, two gun barrels, one gun fairing, and a pitot probe. Each of the gun barrels has a realistic barrel shape, open at one end and faired closed at the other. The gun fairing is slightly larger than the two gun barrels, and gives you the option of having just one gun in the nose.