I can't count or remember all the peeps I've met/known that have horror stories about expandable broad heads. A good friend got them when they were first made and I asked him why try to fix something that ain't broke? and he laughed. He was not laughing when he went all the way to Ohio to hunt w his new heads. He had a 180/190 class buck come trotting down a logging road. He stopped him broadside and released. The head opened w the shot, "screamed like a bottle rocket " his words, and corkscrewed towards the buck that was gone before the arrow got near it. He said he heard that big old buck running away for about 5 mins. Many stories of hit deer never found because of hitting bone w shallow penetration, or no pass through/blood trails w a good shot and many stories of deer found days later after days of looking and spoiled meat. I don't know why they are still popular when the old school fixed heads work fine.
