For a commercially available option without the budget of the custom guns, take a look at the Armalite AR-50. It is a very stable and accurate platform that in concept is designed around a single-shot test barrel and action bolted to an aluminum shooting bench with an adjustable cheek piece and a trigger. The rifle has very little felt recoil and is sub-MOA capable out of the box with decent optics, and it costs less than half of what most competing rifles cost. I think my brother paid about $2600 for his, though he now has about $6000 into it with optics, the drag bag, bipod, loading dies, ect.