not a fan of loading the tube for all of the reasons mentioned above. for carbon shafts, the better route for me was adding more point weight. in fact, ridiculous amounts of weight that upped the foc a huge amount. i found that the added front weight (100 to 200 grains) had no ill effects on arrow flight (no spine issues) with carbons. penetration and arrow flight actually noticeably improved. this is with beman 500 shafts, a 55# longbow with 29" arrows, and 300 grains up front for 29% foc and a 585 grain arrow. however, i did notice spine issues (weak) with alums. upping the front end weight might work for ya, won't know 'till ya try!