“If one gun was good, three were better.” Col Jacques Naviaux, VMFA-122
No fewer than 11 US Marine Corps (USMC) squadrons flew versions of the F-4 Phantom II in Southeast Asia from May 1965 through to early 1973. Although one deployment was from an aircraft carrier, and included a successful MiG engagement, most missions were flown from land bases at Da Nang and Chu Lai, in South Vietnam, and Nam Hong, in Thailand. Rather than the air-to-air missiles that were the main component in the original F-4 armament, these aircraft carried an ever-expanding range of weaponry. While most flew daily sorties delivering napalm, Snakeye bombs and big Zuni rockets, some toted 24 500-lb bombs and one strafed with up to three 20 mm gun pods.
At Da Nang in fact, VMFA-122’s armament team devised a three gun-pod wiring configuration for F-4B BuNo 148378 (dubbed the `F-4V’ in honour of squadron CO, Lt Col John M Verdi), giving a combined rate of fire of 6300 rounds per minute from pods on the centreline and wing stations. As told by Peter E Davies in his book US Marine Corps F-4 Phantom II Units of the Vietnam War, the configuration reportedly made the F-4B ‘an outstanding gun platform’, although the recoil effects, particularly if one wing-mounted Mk 4 pod jammed, required careful management. Col Jacques Naviaux flew with VMFA-122 at this time;

`We had been the first, and probably the only, F-4 squadron to use the gun pod for air-to-air gunnery in Stateside training — our wonderful executive officer, “Bear” Waldvogel, had spectacular aerial gunnery scores. And Lt Col Verdi liked firepower. If one gun was good, three were better. The gun was seldom used by most other units because of a well-deserved reputation for jamming after firing about ten rounds. We had a sergeant in VMFA-122 who loved that 20 mm gun pod, and he made them work. We went from averaging ten rounds between stoppages to 14,000 — an effort entirely attributable to our dedicated and totally superior Marine Corps ordnance sergeant.
`The gun had another problem. We started picking up what we thought were hits from enemy fire on the radome. However, the pattern of hits was associated only with gun firing. It was determined that the high-explosive rounds were tumbling and detonating in front of the aircraft, so we were taking shrapnel hits from our own ammunition.’
The squadron fired more than 43,000 rounds in May 1968 alone, many of them against enemy forces close to Chu Lai. Gen William ‘Spider’ Nyland attributed the squadron’s gun pod success to Verdi’s determination to ‘put the manpower on it and keep it lubricated and tuned up. Operating out of Chu Lai, there was so much sand, grit and crud in the air that it would just jam up — the weapon was quickly dubbed the “1000-lb single-shot rifle.” There was a place for it in CAS, but mostly we relied on “nape and Snake”.’

US Marine Corps F-4 Phantom II Units of the Vietnam War is published by Osprey Publishing and is available to order here.
Artwork Courtesy of Lou Drendel and AircraftProfilePrints.com
Photo credit: U.S. Navy