Does anybody know much about what went into the rifles that Dave Higginbotham made?  Like which actions he used, or which barrels?

Dave also built a large number of Rolling Blocks off either military actions, or older Sporting actions. It wasn't just one source he used to build his Rolling Blocks.

Dave had his LSR receivers, trigger guards, hammers, and breech blocks cast by TC.  Those receivers he threaded with a 1 inch V thread.  The LSR rifle was a mix of #1 sporting and #1 1/2 Sporting rifle designs.   After his death I acquired his FFL records.  It is clear that he built as many rifles on original Remington RB actions as he did his own castings.  One advantage in the LSR castings was the strength and quality of the steel that TC used.   Dave purchased some of the small parts from me.  Using castings the amount of handwork he put into each LSR rifle was huge.  We often discussed that amount of labor involved in his rifle production. However, I was unsuccessful in convincing him to transition from castings to CNC produced components.