Embodiments disclosed herein include needle-free syringe and cap assemblies and filling tub systems. One embodiment of filling tub system includes a filling tub having exterior walls and a floor. The floor is formed into a plurality of sockets configured to receive and support a plurality of cap and syringe body assemblies, with each cap and syringe assembly received in a separate socket. Furthermore, each socket is configured to receive and support a syringe and cap assembly with contact only between one or more surfaces of the socket and selected outer surfaces of the cap. Methods of pre-filling a quantity of needle-free syringes are also disclosed.
