Though in its infancy, the field of micro tube hydroforming has had recent advancements that make it possible to consider scaling it to the production level. This will require the designers of future micro tube hydroforming process to determine which method of hydroforming will be right for their particular application. This paper seeks to ease this process by providing a mathematical model which can be used to determine the feasibility of using a conventional, tapered style punch to perform the axial feeding in the hydroforming operation. The model considers the punch as a thick walled pressure vessel and uses the punch geometry and process specific parameters as inputs to determine the maximum von mises stress in the punch. The model was found to have an error of 8-12% when compared to finite element simulations, making the model a good resource for designers who intend to use hydroforming for their particular needs.