Ok, I'm doubting anyone will know the answer, but I'll post some pics.
These scopes were radical when they came out in the 50's. My friends Dad had one on a Remington 722 in .222 that was amazing. The first time I looked through his I couldn't believe it. I could not only hit a jackrabbit at 200 yards, but had to decide WHERE to place the shot!
The last pictures show the parallax adjustment with setting from 1000 yds. down to 50 ft. You loosen the end locking ring, back off the ring with the distance markings, manually pull the parallax ring with the screws back toward the distance ring, then turn the distance ring pushing the parallax ring into focus/parallax.