The early history of the development and characterization of a set of three 50 mm diameter piston gauges for primary pressure measurements in the atmospheric range is described, including target geometric specifications and uncertainty objectives, most significantly a relative combined uncertainty in pressure of less than 5 × 10^-6. Apart from the relatively large diameter of the pistons and the cylinder bores, other noteworthy features of the piston gauges include pistons and cylinders made from a ceramic material, a floating cylinder design, and the ability to vary the gaps between each piston and cylinder combination through application of an independent pressure along a portion of the inner surface of the hollow piston. The piston and cylinder elements were measured dimensionally by the National Institute of Standards and Technology and effective areas and associated uncertainties were calculated. The performance of the piston gauges was examined by comparing them, and both mode-of-operation and gas-species dependence of the effective areas were investigated and found to be within predicted limits. After extensive testing it was concluded that changes in the piston-cylinder materials were needed to make the systems easier to use consistently and to reduce uncertainty. This early work was quite promising, and demonstrated the potential of the approach. The project, with some hardware changes, is ongoing.