sprinkler valve distance

[mark.f]

Shouldn't that be of "low mass"? As the mass of the ammo increases (or the friction) doesn't the efficiency (flow, opening time etc.) of the valve become less important?

I believe we're both right. On the heavy end, yeah, valve efficiency doesn't matter as much. But on the (very) light end, negligable pressures can push your projectile just fine (so you don't need much air at all). Inbetween the two extremes.... You have spuds.

I found for very light projectiles the valve efficiency is extremely important. The projectile when approaching the speed of sound is plowing a lot of air, so having lots of pressure behind it at high speed is important. Energy = 1/2 Times Mass Times Velocity Squared. If possible, doubling velocity is more important than doubling mass. Valve efficiency matters.

Did you know you can dent car doors with marshmallows?