If your brother isn't use to shooting selfbows then his draw length will probably be a couple inches shorter. Once he has a couple break on him even shorter
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. Anyways, like Pappy mentioned, Osage will take a great bend. But the wood is very heavy, and more important, very elastic. Once you make an Osage bow over 66" long you'll probably start experiencing a lot of limb vibrations or hand shock. Stiffer/longer riser section helps. So does stiffening mid to outer limbs IMO......Art