A fastener magazine for a fastener driving tool has a movable guide that allows fasteners of various lengths to be loaded in the magazine. When engaged, the movable guide sequentially directs each fastener's movement during a drive stroke. When disengaged, the movable guide does not interfere with each fastener's movement during a drive stroke. In the engaged position, the movable guide prevents a fastener from complete backtracking back into the magazine during a drive stoke, which otherwise could potentially cause a jam condition.