Tool must penetrate at least 1"... flipping the inner base out of the way...
... or this won't work. When I just depressing the inner base slightly, which would "seem" to work, apparently the inner base was still preventing the outer base from sliding off. I watched the video again, saw Randy push the tool in at least an inch, heard the "click". When I did that, mine came right off. When the base was off, I could see that the 1" thrust had completely flipped the inner base to the side.
Thanks again Randy and everyone else. I can't imagine accomplishing much in the gun hobby without everyone's great assistance.