The question of rear-facing armament on fighter aircraft touches on a genuine and underappreciated chapter in aviation history, though the answer reveals how decisively propulsion and weapons technology reshaped combat doctrine in the second half of the twentieth century. Tail guns were never a standard feature of fighter aircraft — their home was the heavy bomber. The Boeing B-17 Flying Fortress, B-29 Superfortress, and British Avro Lancaster all fielded tail gunner positions specifically to defend against pursuit attacks from the six o'clock low position, which was the preferred axis of attack for German and Japanese fighters during World War II. The last major operational platform to carry a functional tail gun was the Boeing B-52 Stratofortress, which retained a remotely operated tail turret through multiple variants. The B-52G originally carried four .50-caliber machine guns in the tail position before being upgraded to a single 20mm M61 Vulcan cannon; the B-52H retained that system until it was removed in the early 1990s as a cost-reduction and arms-control measure. Notably, Russia's Tupolev Tu-95 Bear turboprop bomber continues to carry twin 23mm cannons in a tail turret to this day, making it effectively the last operational aircraft in service anywhere with rear-facing guns.
The reason tail guns never migrated meaningfully to fighter aircraft comes down to physics and the speed envelope of the jet age. A rear-facing gun on a fighter presents fundamental targeting and mechanical problems: the firing platform is itself moving at high speed, often in maneuvering flight, while a pursuing adversary is closing from behind. The differential closure rates and tracking geometry make a useful firing solution extremely difficult to achieve with a fixed or even articulated gun mount. Several experimental designs explored the concept — the Soviet MiG-19 and some German WWII-era prototypes flirted with rearward-firing weapons — but none entered widespread service. The more productive solution pursued by both NATO and Warsaw Pact engineers was the infrared-guided heat-seeking missile, which by the Vietnam era had already begun displacing the gun as the primary air-to-air weapon. The AIM-9 Sidewinder and its Soviet equivalents could engage targets from the rear hemisphere with far greater reliability than any gun system could provide.
By the 1970s and 1980s, beyond-visual-range radar-guided missiles — culminating in the AIM-120 AMRAAM with its active radar seeker and engagement ranges exceeding 100 nautical miles — had fundamentally redefined what air-to-air combat looked like. The pursuit-curve dogfight that tail guns were designed to defeat became a progressively smaller slice of the threat envelope. Modern fourth- and fifth-generation fighters like the F-22 Raptor and F-35 Lightning II are optimized almost entirely around long-range missile employment and low-observable signatures, with internal weapons bays that preserve radar cross-section. The retained 20mm M61 cannon on these platforms is there primarily for close-in contingency use and ground attack, not because pursuit engagements are expected as a primary scenario. The gun endures more as a hedge against the failure or exhaustion of missiles than as a central weapons concept.
For professional and corporate aviators, the direct operational relevance of this history is limited, but the underlying technology trajectory is instructive. The same missile guidance maturation that made tail guns obsolete in combat aviation also produced the TCAS resolution advisory logic and ADS-B surveillance infrastructure that now governs separation in commercial airspace. The broader lesson — that sensor-guided standoff capability consistently outperforms close-proximity mechanical solutions — maps well onto avionics philosophy generally. The Reddit discussion, while casual in tone, surfaces a genuine aeronautical engineering question that has a well-documented historical answer: tail guns reached their operational ceiling with the jet age, and the missile made the pursuit attack itself a diminishing threat vector long before the gun could be meaningfully adapted to address it from the rear.