This project was created because my 2 year old son wanted to play nerf guns with his older brothers and sister. The problem is, he isn't strong enough to prime those blasters, so he gets very frustrated and keeps bringing them to me to load every 4 seconds. This unit is manually operated, no springs, no triggers. You simply pull the plunger handle out and push it back in to fire. the harder/faster you push, the harder/faster it shoots. (like a demolisher missile launcher) I tested it outdoors, and when angled,it shoots elite darts over 80ftThis is a simple project that can be completed in 15 minutes and costs under $5.