Doing some measurements today. My Euroarms Remmy cylinder will hold 42 grs by weight of Swiss FFF to 1/8 inch of the end of cylinder. Just barely enough room to seat the ball. This ought to be quite a load. Other measurements are cylinder chambers are .450 Barrel bore .442 Barrel groove .450. 6 grooves .004 deep rifling twist 1 in 18 inches.
Since you asked about cylinders...
Pietta 1860 Army, Graf's FFFg Powder.
Loaded 6 cylinders, increasing the charge as I went and taking measurements.
"Volumetric" | Scale | Depth of ball below cylinder face
40 gr | 34.6 gr | .157"
42 gr | 36.8 gr | .071"
43 gr | 37.9 gr | .035"
44 gr | 38.3 gr | .010"
44 gr | 38.2 gr | .030"
45 gr | 38.7 gr | .017"
Explanation: Poured from a flask into an adjustable brass measure. (It is marked in 5gr increments, so if it isn't set on 40 or 45 it is an approximation). Poured into pan on an RCBS 1010 Scale to measure weight, then poured into cylinder, set ball atop, and rammed home with very firm (and ideally somewhat consistent) pressure. Finally, measured depth with dial calipers.
After I had loaded cylinder 4, it occurred to me that pouring from the scale pan probably wasn't doing a very good job of settling the powder, so for the last two cylinders I tapped the cylinder with my knuckles to settle it a bit. The difference was noticeable. Last note, I had fired this revolver earlier before running this test, so the cylinders were of course slightly fouled.
I suspect that I could fit approximately 39.3 gr of this powder by actual weight, maybe a tad more if I was using a drop tube or equivalent. This powder wasn't as dense as I was expecting. I'll probably do this again with some other powders at some point, just for grins.
