have shot them some years ago, yes they are expensive, thinking it must be now 3$ or more for a round. Very accurate bullet and much power for a shotgun slug at 100 meter. this will be the future of the slug idea, no doubt.
Have their catalog somewhere and remeber a picture of a west african buffalo ( something smaller than a east african cape buffalo) shooting with 12 bore pumpgun and the 12/76 magnum load.