I had the same thing happened to me few years back, it was down to two things. 1: the hammer was hitting to hard on to the value. Causing the spike to drive to deep in to the co2 capsule. And then there's not enough pressure in the co2 capsule to push the spike out. 2: if the co2 capsule only give you say 30 good full power shot and you go beyond that, then there not enough pressure in the co2 capsule to push the spike out. I changed mine to a pcp and cut the spike off.