I got pissed off with my nitefinder plunger because it started to bend whenever I put too many rubber bands on it. I decided to make a new one out of aircraft grade aluminum. It required a mill, a nylon wheel, and a band saw, which I had access to through my robotics team. I haven't replaced the actual head of the plunger where the o ring is, yet, although that seems the logical next step. Also I want to make a badass pull ring for it in some cool shape. Here are some pictures of what I ended up with.
And finally, the entire gun, including rubber bands and my airsoft barrel mod.
The performance is identical to a normal spring modded nitefinder, except the plunger won't bend, no matter how many rubber bands you put on it.