It shoots far and you can make it in 5 seconds.
a normal clicking pen
2 springs.( you can get them from other pens.)
thats all you need.
Put the spring that was already in the pen on the front of the ink cartridge.
Put the cylinder thing in the bottom part of the pen with small side down.
Put the ink cartridge with the spring in and screw on the top.
Now press the thing poking out at the back and your awesome pen gun will shoot.