About a month ago I posted about my second Nerf homemade. The NerfHQ topic is available here.
Propulsion - Air Pressure
Magazine Capacity - 4
Valve - Semi-Auto Homemade
Length - 50 inches (4' 2")
Maximum Range - 250 feet
Accurate Range - 150 feet
It is very accurate and has a fairly high rate of fire. It's rate of fire is not as good as it could be because I did not install an ejector yet and the bolt jams against the shells frequently. But it still has a very good rate of fire for an air pressure Nerf.
Some other pictures:
Picture of entire gun
Closeup on Shells and Magazine
Second picture of entire gun
Bolt Half Open
Tell me what you think.
Edit: An explanation of how the valve works is available here and quoted below.
I am surprised that I never actually explained my system in full before. The links are to pictures of the parts that I am talking about.
The valve is a simple piston style valve. The chamber setup (second picture, this time solvent welded together) encases the piston. To get a seal, the piston has O-ring mounts at three places. The first set seal the main valve (the "trigger valve"). Since this valve has semi-automatic capabilties, the setup set is the shutoff valve (to conserve the air in the reservior). The third set is just there to make sure that air does not escape out the back of the gun.
When the piston is pulled back, air can then escape from the front out into the barrel and so on. However, only air from the chamber is released because the second set of seals prevents extra air from escaping. This diagram that I make should show exactly how the valve works.
The trigger system was just two bellcranks and some music wire (second picture). After the piston is inserted in to the back of the chamber, you hook on a piece of music wire (to connect to the trigger system) and put in a spring and cap (to push the piston forward). Cap the end with an end cap and the valve is ready.
I really like how my gun is really easy to work with and easy to repair. Unlike other homemade valve, this one is high flow and allows you to repair it easily (because you can remove the piston).