I believe ft. lbs. required depends on bullet size. For instance, a 45 cal 405 gr. bullet with only 300 lbs of energy should kill most deer rather quickly if it hits them in the chest b/c it will penetrate deeply enough to take out both lungs, and leaves a large wound channel for blood loss.

I wouldn't worry about it! I've never fired a 243, but they make great deer rifles. You definately have enough gun.

"1200 lbs."...he must be hunting moose