I think that to be acting properly in a rifle the mercury tube should be angled down toward the toe of the stock, that will require a very precise drilling of the bolt action stock, and in syntetics it will require to fill up the hollow with some kind of foam spray plastic.
I was looking into it, and lost interest when I saw how complicated it was.
but I am open to suggestions, I want to put one in a syntetic stock for a Remington 7400 carbine.