They really tempermental. You need higher poundages, over 60, just to get them to light and then they're iffy. You have to turn them fidget with them just to get them to light. And yes, they're suppose to light when they leave the spring. Len got some in and we were playing with them. He was trying them out of different bows etc. While I was there we could never get them to work any where near as advertised. IMO, they're a POS. No consistancy and add $$$ to the price of your arrow. They're bright when the fly but they suck more than perform.