I have just changed the primer from S & B to CCI, and gone from seating on or near the lands to the standard 2.25" COL, and it has definitely improved.
Still think that, given the availability of all things .22, I might switch.
Certainly, groups were good enough today that it's shooting sufficiently well, but I've done so much thinking about this I am almost convinced of 22-250 anyway. But like I said, I suspect I'll give it a bit yet, too much in the way of 204 bits to use first. But at least the powders for 204 seem to work well in 22-250 (alliant stuff anyway)
all calibre