SpudFiles

does anyone know how much propane is in a tank?[/list]

As much propane as the tank says?

Propane is stored as a liquid. As the propane (gas) is used, a little bit more of the liquid is transferred to gas inside the bottle. This pressure usually sits around 90 to 100 psi in the bottle, provided the temperature of the bottle is stable. Note, however, that when propane (gas) is released from the bottle, the temperature drops, which will reduce the pressure.

Sometimes, the meter pipe will require a higher pressure than what the bottle will supply. If this is the case, simply inject half the pressure twice. For example, if the meter calculation calls for 100 psi, set the meter pressure to 50 psi, then operate two times.

Its measured in pounds. The tank will tell you how much it holds.

I'm never sure how much propane is in a tank until I weigh the tank and subtract the tare weight of the tank.

The standard Bernzomatic Propane cylinder contains 14.1oz (400g) of propane. It says so on the label.

Beyond that, "how much propane is in a tank" is a pretty dumb question. Which size tank? New or used tank?

400g propane at STP would be about 200 liters (7 cubic feet) of gas. That would be enough for ~5100 liters (180 cubic feet) of 1x mix. Roughly 3000 shots in a typical sized 1x gun.