Fellers these critters are invincible. Bears are not difficult to kill if you shoot them in the lungs. I have killed several bears in my lifetime. I used trad bows and compounds, muzzleloaders, pistols and rifles. The well placed shot is king. I would advise that if you have to hunt with a prb get a bigger gun. Otherwise, a bullet combo that shoots accurate and is capable of taking whitetail will work. I have killed a slew of hogs and I have never seen no armor. Yeah they got gristle but that ain't no armor and it's not grown as a protective measure against arrows or bullets. I don't shoot 338 plat PB's. Honestly they are too costly. I'm sure they would kill a bear but if you push them to hard you can get mixed results. Just my 2 cents, but why is it a penny for your thoughts?