Jim, The Leatherwood Art scope was what the USMC started using on their M 24/M 14 sniper rifles if I remember correctly. I have a friend that has a orig. Leatherwood scope on his M1A. I have shot his rifle out to 800 yards and found it to be a very good scope. I think it was shortly after Viet Nam when the Corps changed to the straight 10 X Unertal scope. I dont know what the Corps is using now. I know that the 10 X Unertal is a very hard scope to get ahold of.
Hope this helps,
snipertn