I've been trying golf balls with a damp-wet single-layer patch in a 1.75" bore (very smooth), with great accuracy. Not sure yet about repeatability, but that will come. No powder chamber, which puts all the powder on the bottom at the ground side, presumeably giving back-spin. They seem to be flying very straight at 100 yards and further. (I'll start a separate thread, with pix.)
That gets to my question. I wonder what differences there are between windaged and patched golf balls, in pressure, velocity, repeatability in same and accuracy?