RiverRat,
I'll be damned. I would have never guessed that you'd find a picture of that. In fact amazed. And it looks like my "theory" is completely wrong. But you brought up all sorts of things I hadn't considered, such as flex in the receiver, the barrel nut, etc. and I knew it was an apples to oranges comparison given the differences in designs between the firearms.

Glad you caught that before anyone read that, and thought it to make sense, or be valid..so I deleted the post...

Thanks,
FT