Semi-automatic copper airsoft gun (updated)
Posted: Sun Oct 30, 2005 8:29 am
I updated this post, since the original image links were long dead. The gun was also improved since the last post, and is firing pretty reliably. the only problem is that the trigger valve does not reset reliably with the current spring and 300 psi pressure (the design pressure), I may try some lithium grease and see if that loosens it.
Here is how the loading mechanism works. It is connected to the piston valve with a threaded rod,, when the valve opens, the piston moves left and takes the bolt with it.
the advantage to this mechanism is reliability and mechanical simplicity - there is only one moving part. It's also always synchronized to the firing of the cannon. I have adjusted the mechanism so it will only admit a BB into the chamber when the gun is pressurized - the piston face compresses somewhat under pressure and moves the bolt just far enough to open the breech.
A potential disadvantage to this mechanism is the force with which the bolt is actuated - I've had it make marks in the plastic BBs when they got caught at the edge of the bolt, and my first bolt snapped when an alu BB got caught.
This mechanism can be used for other round ammo as well, IIRC someone built a marble gun using it a couple of years ago. I made this gun as a prof of concept for this loading mechanism.
Edit: Here's the other cannon using this mechanism: http://www.spudfiles.com/forums/viewtopic,p,113007.html
Here is how the loading mechanism works. It is connected to the piston valve with a threaded rod,, when the valve opens, the piston moves left and takes the bolt with it.
the advantage to this mechanism is reliability and mechanical simplicity - there is only one moving part. It's also always synchronized to the firing of the cannon. I have adjusted the mechanism so it will only admit a BB into the chamber when the gun is pressurized - the piston face compresses somewhat under pressure and moves the bolt just far enough to open the breech.
A potential disadvantage to this mechanism is the force with which the bolt is actuated - I've had it make marks in the plastic BBs when they got caught at the edge of the bolt, and my first bolt snapped when an alu BB got caught.
This mechanism can be used for other round ammo as well, IIRC someone built a marble gun using it a couple of years ago. I made this gun as a prof of concept for this loading mechanism.
Edit: Here's the other cannon using this mechanism: http://www.spudfiles.com/forums/viewtopic,p,113007.html
Although I don't quite get how the loading mechanism is linked the the pilot valve.