I've met Don on several instances and he is indeed a great individual and he knows his stuff. The PH school John speaks about is without question, the most rigorous in the industry and I'll also add that besides being an accomplished PH and author, he is a rifle and bullet loonie as well!
Well I don't personally know the fellow and I'll take you word he is a swell fella, but if he is stymied by a 400yd shot I would not consider him much of an authority on rifles nor bullets.
Don also happens to be a pretty formidable shot with both handguns and rifles and is one of the top competitive handgun shooters in Zimbabwe.
