A hot loaded 45 Long Colt and a 44 Magnum would be near equal in stopping power. The 45 ACP while a good self defense for human varmits is not a the class with the before mentioned calibers in bear stopping power. Whiole the 12 Ga would be a better choice, its not easy to pack on hiking trips. Conside the Ruger Black Hawk in 45 LC or 44 Mag.