CO2 Bulk Fill Tips?

[angrybear]

CO2 in a cyl or capsule is a liquid under pressure, this is why the contents are filled by weight, not by pressure.
When you open the cyl/cap it allows the internal pressure to drop & the liquid "gasses off".

What you have probably done is allowed the cyl to "gas off" in to the extra volume of the gun, some of that gas will re-liquify, as it expands, but it's pretty slow & not efficient,
what you need to do is actually force some of the liquid CO2 from one to the other by gently inverting the cyl & allowing the gas in the cyl to push some liquid through (where possible weighing the liquid transferred)

once the transferred liquid itself gasses off inside the gun the pressures should equalise & the liquid flow stop.

As above if the cyl being filled is colder it will encourage more gas to liquify.