It's time to increase power, accuracy and practicality...
I've noticed that when it comes to air guns on YouTube, there are a lot of designs that lack simple things yet claim to be Gods own gift to humanity.
Scenario: You've built your spud gun, air gun, whatever... it's neat, well sealed and works, hey it's probably brutal! right? but there's stuff you could improve on quite easily but never thought of, and the results are impressive.
Add a Hop-Up (Accuracy boosting):Edit
What it does?Edit
Those of use who play airsoft (UK/NZ/USA/JAP/RUS) know how important hop-up is. A rubber bucking imparts backspin on the plastic BB's asserting the Magnus Effect (see here), this keeps the BB on a relatively straight course dipping up and then eventually dropping. Not all of our home made air guns will use plastic BB's, in fact, I've only built one that does, but something like a hop-up actually makes a HUGE difference in range and accuracy.
How do you do it?Edit
Making a hop-up isn't that hard, you just need to find a way to get a tiny rubber film to sit pasted on the top of the inside of your barrel. Find some in a textile shop or maybe just invest in a custom made one, they really are quite simply, as the image in the link above shows.
Ball Valve to a Shrader Firing Valve (Power, Accuracy, Range)Edit
For Beginners, the Ball-Valve is amazing. It doubles as a trigger and a control. For all of us, if not atleast most of us, the ball valve was our way into air guns on a home-made level.
Unfortunately for the Ball-Valve, it's simple 90-degree handle makes it something of a problem with air flow.
When you open a ball valve it's far from instantaneous, it slowly turns the internal ball from left to right and air-flow gradually increases, in fact, by the time you have maximum air flow, the projectile has long since left the barrel.
Enter Ben AKA KnightHawkInLight...
KnightHawkInLight has built some great air guns, but his Sniper/Shotgun Airsoft Rifle takes the cake when it comes to simplicity and power. In fact, NSA's MP6's action was based loosely off of this particular valve, and NSA is something of a notoriusly clever Designer.
KnightHawkInLight kicked the ball valve to the curb when he demonstrated the valve workings of his Sniper/Shotgun Airsoft Rifle.
What it does...Edit
Your barrel essentially becomes part of the valve, or the actualy valve to be precise. When you pull the barrel, it moves backwards past the O-Ring, venting the high pressure air straight into the barrel. It is instant. The results put any other valve to shame because the air is vented very fast. Add some high pressure air and you're going to increase your power dramatically. The time between pulling your trigger and the projectile hitting the target will be noticeably different.
How do you do it?Edit
The Impingement valve is very easy to build. You need to be able to pull your barrel through nice-fitting piece of brass that connects to your air tank. In your barrel there needs to be some holes at the very end, with the bottom sealed off with hot glue. A-rebated finish with an O-Ring creates the seal, and a spring holds the barrel forward, closing the assembly.