Star shape at the muzzle means that the bullet carries enough lube to last the whole trip inside the barrel.Actually,that is desirable;much better than not enough lube.
I'd look somewhere else for the accuracy problem;but that's a pretty tall order you're asking for there.Lots of measurements to be taken(bullet size,sizer diameter,throat diameter,barrel slugging,col,trimmed and sorted brass,matching bullet type and weight to the twist of the barrel and a few more) even before beginning to cast your bullets(you are casting them,aren't you?).
Qc