I blew out the back of two carbons just recently. Basically the same thing that you saw but mind did whack into something on the way to the target. our indoor 3-d coarse has a few shots in which you have to go through y's or shoot under and stuff. Well, I jerked and heard ping ping pink and watched the knocks go flying off in the air. No real damage to the arrow except the nock end was cracked up. tossed them to the shop owner and he cuts them down for kids arrows after checking to see if anything else was wrong with them. Probably horribly overspun for most kids though and he admited that.