At the start of World War 1 in the summer of 1914, countries were clamoring for all types of weapons with which to find ultimate victory in. The armored car was something of an infant concept at the time, essentially heavy armored superstructures mated to existing automobile chassis to create a mobile weapons platform. While sound in concept, these creations often proved troublesome in practice, promoting a top-heavy existence and unable to cross even the most basic of uneven terrains despite their reinforced suspensions and robust engines. However, armored cars were valued for the protection offered to their occupants, protection against small arms fire and artillery spray - a key quality that the battlefield horse (utilized in great numbers during the war) could not offer. Additionally, motorized vehicles could ferry troops and supplies at speed over distance and provide a forward-operating fire support vehicle, undoubtedly its most important battlefield quality. Britain, France, Germany and Russia all became large supporters of armored cars throughout the war and were quick to modify all sorts of automobiles in this fashion.
From 1915 to 1916, the United States Marine Corps (USMC) partnered with the Armored Motor Car Company (AMC) of Detroit to develop and produce an armored car system based on a King-branded luxury automobile chassis. USMC authorities envisioned a squadron of such cars supplying mobile machine gun firepower to advancing enemy troops, ultimately overwhelming the enemy and dislodging them from their trenches. The hull superstructure was designed by Captain W.A. Ross to which AMC manufactured the overall concept. The superstructure was mated to the King automotive chassis to form the "King Armored Car". From the outset, the vehicle would be used on a experimental basis intending to fill a need and prove concepts along the way. American had not officially entered the war in 1915 but plans for inevitable participation were not lost on some American authorities.
Two prototype King Armored Cars were evaluated on streets outside of Philadelphia beginning in 1915, becoming the first armored fighting vehicle (AFV) of the US armed forces. Initial evaluations proved the design underpowered, even on ideal roads, and the weight of the superstructure worked against the manual transmission which resulted in a sluggish responding vehicle. The original balloon rubber tires proved awkward in overall handling which led to the rear pair being replaced by a more robust double-tired configuration to help compensate for the added weight while increasing ground contact in turn. A slightly revised version with new turret then appeared and it was this version that was ordered by the USMC in 1916.
The King design was conventional for its time, utilizing six "balloon" type rubber-tired spoked wheels (with spares carried along the sides) in a 4x2 arrangement, a boxy armored superstructure with manually-traversing turret and a front-mounted engine. The vehicles were crewed between two to three personnel, one dedicated to its overall operation (including steering) while another serving the manually-traversing function of the armored turret emplacement and its supplied machine gun. Beyond the primary weapon, the crew relied on any personal weapons being carrier such as pistol sidearms. The superstructure allowed for protection from small arms fire (this proved with .45 pistol shots at close range) as well as artillery spray. There were armored vision ports along the front and sides of the structure with the turret emplacement sitting atop the flat superstructure roof. External shelving was installed along the sides of the hull to support various equipment. The typical rounded headlamps of the time were retained though housed behind hinged door-like horizontal armor plates that could be manually closed prior to battle. The engine grille was also covered in this way by a set of hinged vertical armored doors. A steel obstacle breaching installation was added to the front of the hull. Construction included riveting along its major armored steel plates and operational range was out to 200 miles with fording possible up to 14 inches of water. King Armored Cars were designed with transportability in mind, being able to disassemble prior to transport and reassembled once relocated.
King Armored Cars were delivered towards the close of World War 1 - though none saw service in the conflict due to General Pershing's resistance of such a USMC division. The USMC had plans to ship the cars to France in the event that the war progressed beyond 1918 - further reducing the American reliance on foreign equipment in the war effort. However, the few completed examples remained stateside and formed the "1st Armored Car Squadron" of the USMC, servicing Philadelphia before being relocated to Quantico. Only eight were ever manufactured with five serving operationally with the USMC and at least two with the US Army. USMC marks went on to see an extended service life over that of their US Army brethren, poised to enter the oil fields of Tampico, Mexico from Galveston, Texas (having been delivered from the USS Hancock) under the banner of the 8th Marines should they have been required. Five were then shipped to and actively utilized by the USMC in actions across Haiti and the Dominican Republic beginning in 1919, these then serving into May of 1921 until finally removed from service. From then on, the 1st Armored Car Squadron was formally disbanded and retired in full by 1927. The remaining examples were offered up for sale to private owners or turned into scrap.
The King Armored Car was officially produced in two models - the "Model 1915" of 1915 and the revised "Model E" of 1917 - though several revisions took place between the two major designs. Additionally, some proposed changes were outright abandoned.
The Model 1915 sported a 0.30 caliber Benet-Mercier machine gun in the turret as well as a King Motor Cars V8 liquid-cooled gasoline-fueled engine of 70 horsepower output. The vehicle managed a top road speed of 45 miles per hour and was suspended across a conventional leaf spring system with steering on the front axle.
The similar Model E was completed with a 0.30 caliber Lewis machine gun in a revised turret and a King Motor Cars V8 liquid-cooled gasoline-fueled engine of 79 horsepower output. Top road speed was now increased to 65 miles per hour on ideal surfaces. Additionally, the Model E could be physically differentiated from the former production mark by its use of new wheels with new tires and a sloping rear hull face.
The sole remaining example of the King Armored Car can be seen today at the National Museum of the Marine Corps in Virginia, southwest of Washington, D.C. This example comes complete with a "dimple" in its side front armor (near the front left tire) - evidence of a .45 caliber pistol round testing of the steel. The example also displays a unique four-color camouflage scheme - the scheme being based on photographs taken of the vehicle while undergoing testing in 1916.