Over forty different explosives and types of explosives compositions have been fired in the Small Scale Gap Test SSGT by the Initiation Research Group at the Naval Ordnance Laboratory NOL during the period 1959 to 1972. Many times there have been replicate firing, firing at high and low temperatures, batch-to-batch variational studies, tests of influence of composition on sensitivity, etc. These data -- over 500 data points derived from over 12,000 shots make the data readily available to the reader. Test methods have been described. A minimal amount of discussion of the data has been included to demonstrate some of the ways the data can be used. This report is in two volumes of which this is Volume I.