Hellgate - I've noticed with that my flask and a 35 grain spout, I still only get about 29 grains of Goex FFFg. It is consistent, but some of the granules seem to stick in the spout each time. Same thing with the 24 grain spout that came on the flask - it only throws 21 grains. I've never tried FFg in it - no reason to (and I've only had it a week, and I don't have any FFg with me), so I can't comment. I use a measure to charge the chambers so it's not a big deal really, but still.
FWIW, I don't know what the point of my post really was, but it seemed relevant. Maybe it will help someone...