Jeff; Is that why part of the extension was exposed forward of the receiver. I had just assumed the forend had been modified to move it forward to flush it with the ejection port.
For the really light loads the ring can be moved back next to the receiver behind the spring, thus not subject to loss. This was the recommended set-up for Cutts equipped guns firing standard loads incidentally.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra