I remember when Allen compounds came out. They were testing them for speed at an archery shop. as it turned out my Black Widow 41 pound field target bow shot considerably faster than that Allen compound. The man gave a real simple explanation. "Everyone knows that it takes a while for the arrow shot from the compound to get up to its full speed." That's right he was feeding us pure B.S., problem was that most of the archers there believed him.
Question I have is why do some bows shoot better with hefty arrows better than other other bows shooting the same hefty arrow? some seem to be lugged out with a heavy arrow while others handle them with ease. As example, my target BW compared to a Jack Howard of close to the same pull. In that case I would say the Jack Howard had better cast with the heavy arrow, while with the moderate target arrows the Black Widow had more speed. In some longbows, while they don't slow down as much with super heavy shafts, due to the weight of the limbs in relation to the weight of the arrow, they also don't like very stiff heavy arrows, which most of the time makes it a wash. I have seen longbows, John Schulz built, that gained efficiency sooner with moderately heavy arrows and ended up gaining speed over another normally faster bow, once again I would call that better cast.