Cast some .54 TC maxis last night just for mental release. Been really stressful on the job and needed to do a little lead therapy!
I've been fairly inconsistent with my large cast boolits and it's been a bit frustrating, but finished on a good note. I found that if I didn't let the overflow set up solid, and kept dropping a little on it to keep it liquid for a few extra seconds beyond when it wanted to "set", the finished product looked quite superior overall. Excellent fill out around the grooves and base and quite consistent. I confirmed the last handful by weighing them (they were the last 6 I cast and I separated them) and they ranged between 413.5 - 413.9 grains. A handful from the "pile at large" ranged from 407.3 - 411.8 grains, but with distinct groups or clusters very close in weight within the range.
I'm sure it's consistency of pour and technique that is causing the gaps, so I decided I'll melt them all back and recast again using the method on the last 6 and see how they come out. I'd read someone recommended that on roundball moulds with their ladle pour, but I hadn't tried that on my bottom pour conical mould. So now I will!