hondaxr650r26,
Did you totally disassemble the linkage and powder measure when you cleaned it? You should have disconnected the linkage and removed all the inserts, removed the drum, and then wiped everything down with a degreaser such as your brake fluid. You also need to use a Q-Tip to clean inside the linkage and powder measure. If you have cleaned it properly then make sure that you have the proper inserts in the linkage. When you have the setup correctly with the proper inserts the drum should move immediately when it comes in contact with the case. If you don't have the right inserts in and the case goes up in the linkage before the drum moves you have a gap between the insert and the powder measure where powder will collect as is a problem.
Once you get the problem resolved the powder measure should not vary anymore then 0.3 grains; a RCBS powder measure help considerably. However, you do need to check your powder dispenses regularly, but only after you have measured many rounds and verified it is repeatable and does not have a deviation higher then your recipe can tolerate. I don't like any deviation over +/-0.3 grains on extruded like your varget, +/-0.1 on flake, and less then +/-0.1 on ball. With flake and ball powder I check every 25th round, but on extruded I do it ever 10th round. Those people that quote the ungodly rounds per hour don't check their dispenses regularly which in my book amounts to unsafe reloading practices an inherent flaw with progressive reloading and the use of powder measures.
When using a powder measure pick a load that fills the case at least 60% that way you'll immediately know if you have double charge because you will have to stop and clean it up. Also choose a load that could tolerate +/-0.5 grain deviation safely, but by all means you powder measure better be much more consistent. Lastly if you are reloading on progressive try to choose either a ball or flake powder the dispense much more consistently in all powder measures; for.223 I am using Data Powder 2200 that doesn't deviate more then 0.1 grain occasionally but I still check ever 25th round.