 There are minor differences between the variants; to select "FIRE" on the Howa rifles the selector lever must be pivoted 180 degrees from "SAFE" so it is pointing forward towards the muzzle (where "AUTO" would be on a selective-fire rifle), while on the Sterling rifles, the "SEMI" position is the same as the "SEMI" position on a selective-fire rifle; 90 degrees from "SAFE" with the selector lever pointing down.Towards the end of AR-180 production at ArmaLite's Costa Mesa shop in 1972, some unused AR-18 lowers were used to assemble AR-180s.The "SEMI" and "AUTO" positions were scrubbed and the "AUTO" position was relabeled "FIRE".