What materials were used in the ultra light Bretton O/U guns Roger Barlow used to write about? Probably mostly aluminum, given the time frame; I've never seen one, but recall they pushed the design envelope.

I talked to Ken Genneco about insert tubes for the infamous "Basket Case Optimus". I was considering Briley Ti, he showed me aluminum ones he makes that are similar to the Purbaughs from a few years ago. Seemed even lighter, but hard to tell when just tossing them in your hand. Genneco can make a single gauge reduction (12 to 16) while I believe the Briley require two reductions (12 to 20).