A bolt catch assembly configured for operating with rimfire ammunition for use with a firearm including a receiver with an exposed receiving chamber. The assembly includes a bolt catch actuator housing supported in seating fashion relative to the receiving chamber and communicating with an attachable magazine. A catch actuator is supported in elevatable fashion relative to an end of the actuator housing. A bolt catch component and integrally formed actuator catch engaging portion is slaved to the catch actuator in order to be displaced in response to elevating motion exerted upon the catch actuator, such as by a follower component biasingly disposed within the magazine. The follower, in its uppermost displaced position within the attached magazine, engages a tab associated with the catch actuator which extends over a communicating interior of the bolt catch actuator housing in communicating alignment with the exposed receiving chamber. An end configured location of the bolt catch housing includes a step and ledge profile for supporting an underside of the catch actuator in each of a seated rest position as well as a follower induced and upwardly displaced position.