Chemical-Looping-Combustion (CLC) presents a promising technology for heat and power generation while concurrently facilitating CO2 capture. It prevents the mixing of flue gases with air, eliminating the need for post-combustion gas separation. However, a key challenge with CLC lies in ensuring sufficiently high gas-solid mass transfer in the fuel reactor, to achieve the highest possible fuel conversion and avoid expensive oxy-polishing stage. This study investigates the impact of random metal packings such as RMSR on fuel conversion and mass transfer in a bubbling bed fuel reactor. This packing has a void factor >90% and have only a limited impact on pressure drop and solid flux, while physically preventing bubble growth and slugging. CLC experiments are conducted in a stainless-steel reactor with I.D. of 7.8 cm with gaseous fuels, such as syngas and carbon monoxide. Findings indicate that RMSR packings exhibit a noteworthy enhancement in syngas conversion, reaching 1.0 at 840°C, thereby suggesting their potential to facilitate complete fuel conversion and obviate the necessity for post-combustion oxy-polishing. To study involved phenomena further, cold-flow experiments are performed and a mass-transfer model is introduced to analyze the different mass-transfer steps (intra-particle, particle surface to emulsion gas, and emulsion gas to bubble gas) in the reactor. Model analysis shows that the main resistance for mass transfer occurs across the bubble-emulsion boundary. The incorporation of packings enhances the mass transfer coefficient across this boundary by up to 23% compared to conventional beds, underscoring the ability of packings to improve CLC performance.