Experimental data from an oscillating circular piston positive displacement flowmeter are described which focused on leakage flows and wear. This is the second part of a two part paper on the experimental tests, the first part concerned piston movement and pressure loss. In this paper the leakage across the meter is reported for key parameters including: flow rate, liquid density and viscosity, mass of circular piston, surface coating and length of connection pipes. In addition to the average leakage over a period of time, the leakage past a stationary circular piston was measured during a simulated oscillation. Wear tests were run for both stainless steel and carbon pistons to identify the affected areas of piston and chamber.