A few tid bits of information can help us to help you if you give it to us.
First what powder are you using?
Second What kind of press, and powder measure are you using?
If you are loading on a progressive, or semi progressive it would be advised to use a good metering powder. Fine ball powders tend to meter well, though they tend to not fill the case very well. Bulky powders can clog the mouth of the funnel causing what is known as bridging. This can keep a case from getting enough, or any powder. It can also lead to the next case being over charged as well.
Take 10 cases. Charge each weigh each charge seperately. If they are to within .1 grains of each other then that is good enough provided you are not on the thresh hold of a maximum charge. Now throw 10 more charges, and weigh the whole bunch. Divide by 10 the number should be in the area of the 10 single charges you threw before. If not then you should either check your powder measure. Or you will need to weigh each charge by hand. Or better yet get a better metering powder.
No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.