Here's a picture of the kind of guns that were at the ARA Nationals. I took these last year up in Wright City, MO where they have the ARA Nationals each year in Sept.
Most of these guys use one piece rest.
That red and black stock is a McMillan Edge stock.
That's a huge range. They have 60 benches there where that picture was taken from. They have another 20 benches up on top the hill where they have most of their monthly ARA rimfire matches.
Here's the website for the range. It's actually called the Bench Rest Club Of St. Louis, but really it's in Wright City, MO.