Abstract: A sealless die assembly with a backing element is disclosed. A first die assembly cooperates with a second die assembly to form a sample-holding chamber. At least one of the die assemblies includes a die and a housing that are separated from one another by a radial gap such that the die is rotatable relative to its housing. A thin film is positioned to bridge the gap between the die and its housing to maintain pressure in the sample-holding chamber. A backing element cooperates with the die housing to interface with the film, and the backing element is spaced from its corresponding die. The backing element helps to transfer torque from the sample to the torque transducer. The die assembly may be incorporated into a rheometer or other sampling measuring apparatus for testing process characteristics of a material.