Thanks for the replies, I was going to just turn it off as suggested.
I then started thinking (not always a good idea) what if I damaged the threads on the lower.
I was going to take a finger drill of proper size, get rid of the dimple.
Then with the resources offered here I thought I would ask.
Again thanks for the replies.
charlee
.
The threads are on the extension not the lower.
You do you but the proper way to remove the castle nut is turning with a proper wrench. It will come right off.
It's been done that way for decades.
Good Luck.