jonnyboy wrote:Nice idea, although in my mind a semi auto would be more efficient. As far as feeding goes something like a blow forward bolt but with some modification could allow both semi and automatic modes.
With this design, slight pressure on the blowgun should give you a single shot capability.
May want to go larger orifice valve at lower pressure and size the chamber for a positive pressure on projectile exit. To pull it off may require designing and building your own low pressure pop off valve.
Good points, though you can buy adjustable relief valves.