Well; I have 280 grit also. Maybe I'll do two cylinders of 280 & two with 400 & then slug the bore & see what it feels like.
Had another surprise when I shot the M24 with a moderate load behind the 429421; it shoots about 6" high at 30 yards with the rear sight bottomed out. The Smith is so mint, I don't want to modify it so I've got some store-bought 200gr SWC's coming to try. Hopefully that will get the poi down to the top of the front sight. If it works; I'll just get a mold that drops around 200gr & save some lead. I limit myself to 50 yards in the woods with these 50+ year old eyes & a big deer here doesn't often go over 200# so a 200gr .44 will be fine.