The 3-9 Redfield Accutrac scopes were not used on the USMC M40. AccuTracs were not introduced until the late 1970's. The scopes used on the M40 had the "Tombstone" rangefinding scale and were called Accu-Range by Redfield. Similarly, the Widefields were not contract scopes either. Widefields weren't introduced until the early 1970's.
My dad has been running a wideview 3-9 Accutrac with BDC turret since I was born or slightly before on a LH Weatherby MKV in 270WBY MAG. His has the tombstone reticle in it as well.
He said to me when I was young (pre-internet obviously) he bought it because "it was what the Marines used" (obviously he was slightly mistaken). Fast forward about 28 years later and I ask dad if he ever used the BDC or the reticle as intended. He's like, "What's a BDC? I don't need to range find anything.". He lost or threw away the other two drums.
I myself finally shot the rifle in my 30's. It's basically got a point blank range of 300 yards with factory loaded 140gr Spires on a 5" steel. Dad back in the day always ran 180gr Trophy Bonded Bear Claws on everything.....deer, coyotes, skunks. Everything got a fist sized or bigger hole.
So yeah, he doesn't range find for deer sized targets in his comfort zone. The laughable thing is dad's fellow fudd hunting buddies telling me how good of shot dad is. I'm like, "LOL ...No he's fucking not. He's never thought more than put crosshair on meat....pull trigger."