Here are Federal's published energy numbers for the .30-06 with 180 grain Nosler Accubond:
Load # Cartridge Muzzle 100 200 300 400 500
P3006A1 30-06 Spring. (7.62x63mm) 2913 2547 2217 1922 1658 1423
At 500 yards, it shows 1,420 ft.lbs of energy. The acceptable minimum energy established by the "industry" (whatever that really is) for harvesting a deer is 1,000, so this particular .30-06 load that has 1,420 is well above the "minimum." (For the record, I am not necessarily advocating the merits of the 1,000 energy number, but I'm using it as a reference since many other - supposedly more experienced - hunters, go by this number.)
Now, if this Accubond load hits 1,423 at 500 yards, then I seriously doubt that it will reach 1,000+ energy at 1,000 yards. You are right, a ballistic software program should give more accurate numbers, but I would imagine that this load at 1,000 yards would have less than 500 pounds of energy. While that should be certainly enough to knock down steel plates (and certainly punch through paper) it would fall way short of the 1,000 energy number.
On the other hand, if someone is shooting a .300 Rem Ultra Mag, then I guess that the 180 grain bullet could maintain about 1,000 ft. pounds (or more) at 1,000 yards, but a .300 Ultra Mag isn't exactly a standard deer hunting cartridge.
Again, I don't have the benefit of a ballistic software program, but I just can't see how a standard .30-06 can still reach a minimum of 1,000 pounds of energy at 1,000 yards with "deer hunting" bullets.
BTW, for what it's worth, I have also understood that the "magic" minimum number of energy for an elk is 2,000 pounds. I believe that the KO (I think that is what it is called) is a better formula to use because it also takes into consideration the diameter of the bullet. Otherwise, in using just the 1,000 number for deer, people could be mislead into thinking that shooting a deer with a .222 or .223 Remington at close range is just fine. But while I know that some people can, and do, harvest deer relatively humanely with such little loads, they leave much room for error and only the most skillful of shooters, and hunters that have enough patience to take the perfect shot under ideal conditions, should attempt such shots.
Zachary