We had a Factory Class at our club benchrest matches. Ole Mr. Wright was pretty strict on the rules governing what constituted a factory gun. The rifle had to have a factory barrel, stock and trigger, no forearm adapters or lead sleds allowed.
If doing load testing I prefer to use the most stable rest setup available...
I met Dick when Randy Robnett and I traveled to Holton, Mi. for the IBS Score Nationals in 2010. Dick and Jeff Aberegg took us to dinner one evening and we enjoyed a few adult beverages together.
Good shootin'. -Al