If you take a 55 gr Sierra HPBT and run it out at 3000'ps it has just about 1090lbs of energy. At 200 yds it has shed about 1000'ps and has about half of the energy. At 300 yds it is moving at 1650'ps prox and has energy around the 350 lbs mark. Depending on what you are shooting at determines if that is acceptable. For rabbits, 300 yds is acceptable. For deer size animals, I'd stay under 150 yds or expect to lose wounded deer. Putting the bullet on the target is one thing and the 223 is quite capable of doing that at yardage. Reliably killing an animal is a different thing.