10mm and 12ga slugs are the antithesis of all these solutions. But as always shot placement is most important. Knew a guy that trained Oregon Parks and Wildlife Officers started carrying 10mm S&W 610 (moon clips) as the side arm for Rangers, and a 12 ga with slugs as backup. 2 man officer teams usually, and the SOP was if a bear attack happens hug the bear, and the partner (behind) would shoot at the head, empty weapon, then transition to the 12ga, then put it under the bears neck and drive the shotgun through the bear's skull while unloading. They said that strategy worked in all cases where deployed with minimal harm to the guy getting a fur hug....hearing loss aside!