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Old May 6th, 2009, 01:23   #35
aznpos531's Avatar
Join Date: Jan 2009
Location: Toronto
Instead of starting a new thread I'll just ask all my questions about this gun to this thread.

I've finally discovered the apparently common and infamous problem where only 3-4 shots can be fired before needing another fill of propane. After searching on this forum as well as others, I've read many differing suggestions to solve this problem and am now a little confused. The two most popular suggestions seem to be warming the mag before a fill and (funny enough) cooling the mag before a fill. Both of the suggestions seem to have sound reasoning behind them and may both work for all I know. Logically though, I'm leaning towards cooling. Here's the reasoning:

Warming the mag
Warming the mag before a fill (commonly done with body heat from the hands) seems to make sense as it will increase the pressure of the gas in the mag. However, to me, it would make more sense to fill the mag and then warm it to increase the pressure of the propane inside the mag as opposed to the air in it, which would actually cause less propane to enter the mag.

Cooling the mag
Cooling the mag (commonly done by firing off the gun with the mag half full of propane before a full fill-up) makes more sense to me. When the mag is cold, the pressure in the mag is lower than if it were at room temp (or when it's warm) and so more propane is able to enter the mag during a fill.

Either way, the mag stops filling when the pressure between the mag and the propane tank reaches an equilibrium. Putting the two together may be a solution:
1) Warm the mag (you may need something warmer than body heat; perhaps warm water) with the release valve open.
2) Close the valve while the mag is still warm.
3) Proceed to cool the mag (don't use the firing-the-gun-half-full method; it defeats the purpose of warming it; use cold water perhaps). Make sure the valves are closed when cooling
4) Fill the mag with propane while it's still cool.

The reasoning behind this is when you warm the mag with the valve open, the air inside the mag expands and the now excess air can come out. When you close the valve (thus locking out the air that escaped) and cool it, it causes the gas to contract, thus creating a vaccum. The relatively low pressure in the mag will allow more propane to fill the mag. Ideally you'd warm the propane tank to increase the pressure, but that's generally not a good idea (don't do it!).
If you warm the mag with say, a bunsen burner and cool it in say, liquid nitrogen, no doubt the mag will probably implode! However, I don't know if this warm water, cold water thing will damage the mag at all. Of course you'll want to be careful not to get any water into the mag, and that the valves are dry when filling, but I don't know if this will be hell on the seals/blow the seals.

Please comment with thoughts and suggestions and feel free to do patchwork on my reasoning as I'm sure it's flawed in some way.

Last edited by aznpos531; May 6th, 2009 at 01:27..
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