Abstract: A tool assembly is provided for facilitating insertion or removal of an end of barrel choke of an interchangeable choke shotgun. One component of the assembly consists of a tool adapted to be telescoped into a choke in driving engagement therewith. The other tool component is a cordless, reversible drive, portable power unit which may be releasably connected to the tool. The tool and thereby a choke in telescoped relationship thereto is driven in a direction by the power unit to rapidly insert the choke or effect removal thereof from the gun barrel. The assembly has particular utility in sporting clay competition where chokes must be changed at each of a multiplicity of target stations.