Great! Thanks Rusty. I read that some can be pumped to about 45 psi, but am not sure what that translates to in shooting capacity/longevity. I'll mess around with the couple I have just sitting in my garage and will get back to everyone.
The rapid fire 20 is a fun gun with a great machine gun sound, but it's not that effective in nerf battles. The single shot mode is not that accurate and shoots inconsistant distances. The rapid fire mode is the best for short distnaces and sweeping across a moving/difficult to hit target. Although, half way through, it looses much of it's power. I find it best to shoot 2 or 3, pump up and shoot some more. I still have not tried to modify this one, but I can imaging it could get some serious hits if it shoots longer range.
I joined recently and sounds like in the nick of time. I have not contributed much since I'm trying to learn as much as I can. My friends and I have just gone nerf crazy and are trying to modify some of our guns. Let me tell you all, this is a great site and hope to, not only learn, but share if anything cool comes out of my workshop... thanks