wow ive got no clue how i missed this build.
very very impressive and would love to have a set up in this as most of the people just go with blowback.
while id watch the trunnion for cracks as you said, with the reduced force your putting on there it would "seem" to be fine.
you offering any of this work as a conversion service..
or maybe some contact infor for the Litchendberg magwell deal?