The oring is a replacement for the adjustable post one, figured peoples might be a bit worn. I just re-measured all the specs, they are identical to your adjustable draw ones, so I'm not sure why it wouldn't be working. Is there something maybe just down in there or on the adjustable post not allowing it to screw in all the way?
Not that I can see. I tried my adjustable post on both the satin and polished solid caps I received and it does the same thing on both - screws in until just past the threading on the adjustable post and then it won't go any further.
If I just push the post in until it catches on the threads, I get maybe about just under one full rotation as I try to screw it in and it just stops. I can get about 2 1/2 rotations on my stock cap.
Pics, sorry for the blur. Lighting is bad in my room.
Adjustable cap, with post screwed all the way in:
Satin cap, with post screwed in as far as it will go:
Polished cap, with post screwed in as far as it will go: