If you are talking about a real live NBRSA or IBS Legal Heavy Varmint, then any of the common stocks that are legal for that class will do just fine. I use a purpose built Robertson BRX that weighs about 36 ounces for my HV 30BR.
A little advice, some will disagree. If you are going to build a real life HV, get a stock that has some extra material where it counts. The trend in past has been to make stocks as light as possible to satisfy the requirements of LV-Sporter at 10.5 pounds. I am not a fan of stacking weight in a LV stock to get weight. Build a true HV from the get-go. If you are willing to order a stock, the manufacturers will add more layers and internals to make the stock stiffer and stronger and get the weight distribution right.
If the legality for Class Participation is not a issue, the Shehane Tracker is very popular........jackie