A hell of a lot of elk have fallen to the 150 gr. bullet and a hell of a lot have been killed with a .270 with a 130 gr. bullet. Shot placement is the key to any quick kill on any animal, big or small. My 30-06 prefers 165 gr. boat-tail bullets; shoots a one inch group at 100 yards with them and has plenty of killing power. If your rifle groups well with a 180 grainer or a 220 grainer, shoot the bullet that groups the best in your rifle.