Disclosed is a free-flight hammer, impact-printing apparatus including a shifting hammer bank having a plurality of interchangeable hammer modules. Each hammer module includes a plurality of individual linear motion, slidable hammers which are mounted in a side by side relationship in a hammer housing. Each hammer housing also includes a hammer-return spring mounted adjacent a hammer for causing the hammer to return to a set position. The hammers are caused to strike a moving record medium by a plurality of interchangeable actuator modules which each include an actuator assembly. Each actuator assembly comprises a stator housed in a stator housing, a solenoid assembly and an armature. The solenoid assembly is mounted between the stator and the armature. The armature actuates pushrods, which are slidably mounted in the stator housing, in order to cause a hammer to strike. A second actuator assembly can be mounted behind the first actuator assembly relative to the hammer modules so that the first actuator assembly can actuate two hammers through the interaction between the two adjacent actuator modules.