I know but it's still an effective range of the rifle. Those ranges you get on paper are not the ultimate range of a rifle, that's my point.
Another point on the 5.56mm, if a person is stood behind a thick tree. The M-16 or any other 5.56mm rifle for that matter won't be able to get him. However the SLR and most other 7.62mm rifles will put a hole straight through it, and at least, injure the person behind.