Hmmm! The Native Americans here in the Northwest went after Grizlies with 40# and 45# bows. The trick is in the arrow. Bird points! Small obsidian points penitrate like crazy! Arrows will go in one side and out the other. Bear has no idea they are hit so you can put a couple more through before he even know he is dead or just sit back and leat em blead out.
Personaly, I have no nead or want to hunt bear. Look to much like a big ol dog to me! Plus, I dont think they taste too good!
By the way nice bow Pat! How the heck do you get so much time to make bows? Please tell us your secret!