I will not be shooting the wood arrows out of my bow because I realize what you said above. The kids can shoot them a long time out of there 15 pound bows without regard of spine. If the brand new aluminums are spined to heavy for my longbow I will use them for flu flu arrows. The coolest part is the quivers and rubber blunts and squirell broadheads. The flu flus are new as well never been shot and they say spined up to 60 pounds, I shoot 45 pounds. I appreciate your concern. I already have used the wealth of information on this site to build a well tuned, hard hitting, super tough arrow to use for my deer, hog and turkey hunting. I also kind of wondered if maybe these used to belong to a tradganger.