There is no guide line in what gouges you will need for rifle building, nor in any type of carving. As Jerry stated, by having different shapes of gouges, you can use them to stab in so as to get a better, smoother curve. To compound the problem in choosing, there are also different widths in each curvature size. What you might want for carving, may not be exactly what you want for shaping the stock, but they could still be used for that purpose. Most knife manufactures start at 2 (being only slightly curved) to 10 or more (being really rounded in shape). I remember reading somewhere about suggested sizes, went out and bought most of those sizes, those knives were the least used ones that I now have. For me, I thought about what I needed to get certian things done, what would make life easier for me. I went and bought a few of them, and as I used these tools, I based my next purchasing decision, and I slowly built up what I now have. Yes there were some bad choices, that can't always be avoided. I have a collection of Phiel, Two Cherry, Flex-cut, and custom made with Flex-cut being the majority. With proper care, storage, and sharping, they all will do the job. Carving can be addictive, I've done a lot of caricatures and reliefs that were just as fun to make as rifles, the only way to learn is by doing it.
