Elk billets work OK. They can be a very large diameter. They almost always have a curve due to the first brow tine comming off so close to the base which I think is a negative. Have found that wolf killed horns make better billets than shed because you can use some of the bone below the base as an extention of the billet. Makes for a much tougher billet. I don't use a lot of flints, but some jaspers and agates respond to them well. Also does a good job on obsidian once you have made a couple of good platforms. Watcher