"The last I knew (and this might have changed) GE silicone contains acetic acid (that's what gives it a vinegar smell). I would be afraid that the acid might eat into the blueing or cause stains. Just a word of caution."

Loco Weed, that's really important to know. I had noticed the smell, but did not know it contained acetic acid. I also noticed that some of the other silicone, or similar to silicone, sealers do not have the same smell. Maybe they do not all use acetic acid. All of these are recommended for use on steel and aluminum, among other things, but I guess a little research and experimentation would get us to the exact correct one.

But I think this concept is the way to go, for getting all the "play" out of an attachment like this, and keeping it secure under many recoil cycles. In fact, if it doesn't move around, it should also eliminate all, or almost all, creation of shiny spots on the bluing or anodization. It creates a cushion.