PJ
Several years ago, US rules for hunter underwent a nearly complete revision (reversal?).
Currently, anything that makes weight, has a tapered bbl no longer than 26" and 'looks' like a hunting rifle is legal -- factory or full custom. It's pretty gray but, seemingly in the opinion of almost everyone, it's an improvement.
The change was led by Alpine Machine Company's introduction of new hunter rifles that were 'factory built' (Alpine Machine is a small, licensed firearms manufacturer) to be specific to the rules for silhouette hunter. That more or less forced the NRA to open up the class.
Alpine designed a fairly radical new stock that is 'nearly' (but not absolutely) perfect for the game and then released the sales rights to Nesika Bay.
Mark Pharr took that stock, fixed its few problems and now markets the improved version under his name.
I think that you'd find that anyone who has used one would agree that Dave and Hornet are right -- Mark's stock is superior to anything else on the market for silhouette.