Pinky, my targets were 40 years ago, starting with a SMLE at about age Fifteen. Thousand yards was an"easy" range because the bull was six feet across.
I forget which were the "harder ranges you may be right from memory somewhere between five and seven hundred was hard.
These were the days when the ammmo was free and I could buy a brand new jungle carbine still in cosmoline for $10.00 at the club.