Just look at the range data on there website. They usually say what custom rig they use or just call.. I gotta say hart barrels in ny is excellent place. I visited them and fell head first, what a bunch of outstanding folks.
The PA 1000yd range is mostly Kreiger and Broughton with some Bartlein. I'm pretty sure the new 600yd record was set with a Brux. It seems like short range 6ppc and .30BR stuff still has a lot of Shilen and Hart's but the LR stuff doesn't so much any more.