Did you see the television programe a while back, when just such a replica was tested. Boffins took measurements and made all sorts of cautious predictions about how far it would shoot an arrow and what the penetration would be at x, y and z metres. Put the bow on a machine with a known controllable, measurable pull. Shot the arrows and the results were pretty pathetic. Gave the bow to an archer who took it into the field. He shot an arrow much further than the experts said was possible. Then he trimmed the enormous and ridiculous white flights to about half. With drag reduced, the arrow went twice as far as the boffins said it ever could and made a neat job of penetrating a pig carcass at extreme range. Guess those Neolithic guys never had to worry about nay-saying boffins or extravagant fluffy feathers.