Some variation is OK. How much have you got?
The diameter is easy enough to check. You should be able to eliminate any 9mm bullets from .40 caliber bullets. I doubt if they would even stay in the case.
Plus or minus 5 grains of bullet weight is not all that much (depending). If you are talking about a 50 grain 22 centerfire round loaded near maximum or minimum on top of a powder that has a narrow range of charge weights, I would worry. If you have 180 grain 30 caliber in a cartridge and powder that has a wide range of charge weights there is less to worry about.
Your bullets in the weight range you have - well that could be a meat math problem.
Weigh your brass. Figure out what the weight variation is there.
Weigh the loaded rounds.
If your powder charge weights are all the same, you should easily find the cartridges with too-light and too-heavy of bullets.
If you loaded near the edges of the performance envelope, it might be worthwhile to pull the bullets. But if you were in mid-range, you could exercise some judgement and discretion. The problem is, the 40 caliber is a high-intensity (high efficiency) cartridge with little "wiggle room" for propellant charge variations (and, by extension, bullet weight variations with a given powder charge).
I would use my judgement. But then, I shoot handguns and mostly magnum cases with charges in the lower end of the power range. (For example, Bullseye or Unique in .357 and 44 mag cases at around 1,000 fps with 158 grain or 240 grain bullets). I am nowhere near the pressures that would result in a (too low) stuck bullet or (too high)over-pressure. If I was using H110 and pushing beyond 1500 fps I would pull them if I couldn't rule out a dangerous load by other means.
Last edited by Lost Sheep; December 10, 2012 at 11:09 PM.