Some recent conversations both on-line and off-line with folks having accuracy problems made me do some thinking. The ones I've talked to most often use a bullet if it looks good. Those who weigh them often decide 2-3 grs variance is good enough.
My opinion on it: All the bullets I shoot in my Sharps are weighed within 1/4 grain up or down, and if one goes over it's because I didn't hit the cutter straight and there's a teat on the base.
I know some think that excessive, but to put it in perspective, go to the loading room and get on #8 shot, lay it down, look it over, weigh it, will be real close to 1 grain, depending on alloy. Would you shoot a bullet that had this big of a visible flaw?
Now remember, if the bullet is 1 grain under normal weight and you know your alloy is consistant, then you have 1 or more internal flaws that add up to a flaw that size. Depending how far off center they are, you have a bullet that don't balance when it hits the air. Kinda like a tire off balance. Of course 2-3 grains you need to get another #8 or two out and look and think.
If your rifle don't shoot like you think it should, then ask yourself how ruthless you were with the bullet sorting. All the case matching, lubes, powder types or primers won't make up for a bullet that won't spin true on it's axis.