I have cast bullets for a plethora of .22's over the years. The most important advise I can give anyone attempting to do so is this: As the size of the bullet decreases, the effects on accuracy caused by slight imperfections increases. A tiny deformity that wouldn't effect the performance of a .30 caliber bullet can cause a flier if found on a .22 bullet. Be very critical of the quality of your cast .22's.
Currently I'm working with .228" diameter bullets out of an old Ideal #228367, 60gr. GC, in a 1912-vintage Savage 1899H .22 HiPower. Getting inch groups at 50yds. (tang sight+middle aged eyes) with 6gr. Unique. Don't know the velocity- and don't really care- but I guess it's around 1500fps. Shows promise for a light turkey rifle load this fall, with maybe a bit more velocity. Couldn't find a .228" sizing die, so I took and reamed out a .225 die, using a #1 size drill bit chucked in the tail stock of the lathe. Worked like a charm.