Looks like it could be either swamp chestnut oak--Quercus michauxii, or chinkapin oak. Chinkapin oak tends to have a shorter trunk and a dark small nut. The swamp chestnut can get very large and has a large acorn, and also should split pretty easily. I'm guessing what you have is chinkapin. Was it growing in a low wet area or on upland? Either one should make a durable bow.