I think you need to push the buttons on that calculator one more time. I think you've got an error in your figures. NO way to get 900 ft/lbs. at 500 yards with the .204, no matter the load of bullet.

On edit, I went to Hornday's web sight and used thier little energy calculator and found that a 40 gr. bullet at 4000fps only has 344 ft/lbs of energy at 500 yards. Even a 45 gr. bullet at 4000fps only had 387 ft/lbs at 500 yards. So for giggles, I kept punchin' numbers until I found a bullet that would carry 901 ft/lbs at 500 yards and it was a bullet that weighed 105 grains with a muzzle velocity of 4000fps. Don't think the .204 can do that!