I did not build these cannons from scratch. They are modified versions of the ones found on Dumpworks’ Messerschmitt Me-262 A-1/U-4 "Pulkzerstorer"

History:
The I-216 was a prototype heavy fighter built in early 1948. It was an unusual modification of the I-215 for the installation of two 76mm automatic Nudelman N-76 cannon (!). These very powerful cannon fired primarily high-explosive (HE) shells and had a relatively low rate of fire and shell velocity. They were not finished in time because Nudelman was busy fixing the quirks of his 57mm N-57 automatic cannon. Estimated top speed of the I-216 was 577 mph (930 kmph). Although it never flew, the I-216 still could be the fighter with the most massive cannon armament in the world.