Garrett recommends the 540 Hammerhead for bear...?
"FIRST CHOICE for defense against heavy grizzly"
"Our 540-gr +P Hammerhead Ammo is the ideal choice for stopping heavy bears at close quarters or hunting them at short range. This Hammerhead bullet has a meplat (frontal flat) diameter of .360”, which is just one tenth of an inch less than bore diameter. With its tremendous weight to diameter ratio (sectional density) it provides end to end penetration on the heaviest of bears, with exit, and does tremendous damage per unit of penetration due to its extremely blunt front end. This load is carried exclusively by NOAA for protection against coastal grizzly attack. It is also carried by the National Marine Fisheries Service and the U.S. Geological Survey for protection from grizzly attack.
For the specific task of stopping a grizzly charge, this ammo has no peer."
Please read Garrett's 45-70 Commentary for more information."
Aside from the obvious need for accuracy, while under pressure, bullets with strongly constructed max' penetrators, from a .429 or .458 diameter ammo, with the highest sectional density, at heaviest weight is what I'd trust to get it right the first and only time.
This is off topic, but these chats reminds me of speed vs. penetration kind of mindsets in karate-do. I am not in favor of speed-tag sparring training, for people with years of basics, that want to go beyond superficial learning to something more practical. Matter of fact, I advocate knockdown karate "jissen kumite" (full contact continuous sparring, usually with no or minimal padding) or "fighting" in the fine sport of MMA, where the karate-ka must fend off tough wrestlers that can tackle and dump or throw so hard bones can break. The lessons I've learned from these controlled sporting endeavors is that simplicity, accuracy, and penetration are principles that creates results, aside from having lots of anaerobic endurance: "out of gas, no offense." This, what I have felt, and with the guidance from cops, hunters, and armed citizen that have shared their traumatic experiences guides my thinking on stopping attacks.
For me, unarmed training, (karate, boxing, and jiu-jitsu) must also be accompanied with weapons training (rifle, shotgun, sidearm, knife, cane, "jo"-stick). And at all times, have fun while being practical, and be respectful, even when the others are wrong.
