March 1966, and found the design unsatisfactory in performance during mud and sand trials. ArmaLite made several minor production modifications to the design commencing in 1965, and the U.S. Army was directed to re-evaluate the AR-18 at the end of 1969. Testing was conducted at Aberdeen Proving Grounds, conducted by arsenal employees and the Infantry Board at Fort Benning, Georgia. However, American procurement officials were not interested in acquiring yet another 5.56 mm service rifle. A number of deficiencies were listed and the testing authority stated that, although the AR-18 had military potential, it needed further development. In 1968, dissatisfied with efforts to market the AR-18, Arthur Miller left ArmaLite. Instead, the AR-180 was sold on the civilian market, while the AR-18 sold in small quantities to police and law enforcement organizations, as well as armies and security forces of nations such as Botswana, Haiti, Malaysia and Swaziland. Still others found their way into the hands of paramilitary groups, such as the Provisional Irish Republican Army (IRA) in Northern Ireland, (see also Provisional IRA arms importation). The ArmaLite rifle was for many years the most lethal weapon available to the IRA. For this reason, it became an iconic symbol within that movement. The Republican ballad "Little Armalite" tells of how the AR-18 changed the fortunes of the organization in its conflict with Britain. The Armalite company reportedly bought 1000 copies of a recording for its salesmen to distribute. The 1980s Republican political strategy of parallel political and paramilitary campaigns was also christened the "Armalite and ballot box strategy". Variants The standard AR-18 versions manufactured by ArmaLite, Howa and Sterling Armaments Company differ only in minor details. ArmaLite and Howa rifles have a satin grey phosphate finish, while Sterling rifles sported two finishes; Serial numbers S15001 through S20000 had a black, glossy enamel painted finish. Starting with serial number S20001, a blued finish was used for the remainder of production. Rifles were normally equipped with a sling, cleaning kit (bore/brush), and a knife-type bayonet with scabbard. An optional bipod with a case was available. The AR-180 is capable of semi-automatic fire only and was externally identical in appearance to the AR-18 with one exception; the selector has only two positions, omitting the third "AUTO" position found on the AR-18. There are minor differences between the variants; to select "FIRE" on the Howa rifles the selector lever must be pivoted 180 degrees