I bet a motorcycle or automotive shock absorber could be turned into a wicked spring rifle... might be on the dangerous side tho! Inspired by seeing one in the dumpster the other day.

They built a balanced piston valve. Very heavy-duty steel, they've run it as high as 500psi. The barrel is evacuated before the shot. There's a nice shadowgraph image of the shock wave from the supersonic baseball. Discussion of the concept: https://youtu.be/E60G3ba4TUA?t=296 The shock waves start h...

I like @hectmarr 's work on these autonomous hybrids. I'm thinking about a design for a single-pump, high-mix hybrid. It seems to me that going for multiple pumps is a waste, since the resistance of the first few strokes is low, so one's arm is getting a lot of exercise just going back and forth. [a...

A few more thoughts: I looks like Hector's little pistol has 16mL chamber, or ~1 cubic inch. I feel a bit silly for planning a rifle around a chamber with half that volume. So, I eked out a bit more performance by extending the lever arm to 24," the attachment point to 6.5," and increasing the cylin...

https://media-exp1.licdn.com/dms/image/C4D22AQE-OLrsX-uJUA/feedshare-shrink_800/0/1620891745542?e=1623888000&v=beta&t=Kbml65sjTyKUzWdow98xZH9aqoBRdawD3QQfYGoqHS8 "22 metre £1.1 million hyper-velocity gas gun. 100 g projectile, which can reach a maximum velocity of 6.5 km/s using 3 kg of gunpowder. ...

So I work at a nuclear fusion start-up these days. We have ~1MJ worth of energy storage in 15kV capacitors, along with a hydrogen gas injection system that operates at >500psi. These are solenoid valves that fully dump within 1 millisecond. They are actuated with a ~5kJ, 4kV capacitor bank. I keep t...