The phase diagram of a model for a uniaxially stressed antiferromagnet of cubic symmetry is calculated using high-temperature series analysis of the ordering susceptibility. It is shown that the model exhibits a bicritical point in zero stress, =0, and that the phase diagram includes a spin-flop-like and an antiferromagnetic phase for <0 and >0, respectively. We have determined the crossover exponent to be =1.33 0.10 in agreement with renormalization-group predictions for a n=3 system. The variation of the exponent along the phase boundaries separating the ordered phases and the paramagnetic phase is discussed in the context of universality.