Board Thread:General Nerf discussion/@comment-35070608-20190120055424/@comment-27306930-20190120201932

The plunger catch (see blue arrow) engages with the trigger catch (see circled) to hold the plunger back when primed. If it's not engaging, there could be a couple things happening. The plunger tube might not be sliding back far enough to grab the catch (too many pennies can cause that). It's also possible one or both of the catches is worn down and not able to engage the other properly.

Another common problem is the trigger catch. Make sure it is sliding up and down freely. Lube if necessary. Also check the trigger catch spring. It needs to push the catch firmly up against the bottom of the plunger tube to hold it back when primed.