The performance of the GlueX Forward Calorimeter was studied using a small version of the detector and a variable energy electron beam derived from the Hall B tagger at Jefferson Lab. For electron energies from 110MeV to 260MeV, which are near the lower-limits of the design sensitivity, the fractional energy resolution was measured to range from 20% to 14%, which meets the design goals. The use of custom 250MHz flash ADCs for readout allowed precise measurements of signal arrival times. The detector achieved timing resolutions of 0.38ns for a single 100mV pulse, which will allow timing discrimination of photon beam bunches and out-of-time background during the operation of the GlueX detector. •A beam test was conducted for a miniature of the GlueX Forward Calorimeter.•The energy resolution at low energies was found to be consistent with design goals.•The timing resolution of the incidence of events was measured with flash ADCs.•The timing resolution was confirmed to be adequate for discriminating beam bunches.