I hope some one can suggest what might be happening. I have a Lyman 55 that I have used with satisfaction. I had been measuring Bullsye for midrange loads and periodically checking the load against a scale. I did not find any deviation in the set loads, this was over a range of loads for 38s, 9mm and 45s.
I have a can of Unique that I've had for a while (the retail price tag on the 1 pd can is $2.95 if that dates it), which seems in useable condition. The problem is that it does not measure accurately through either the Lyman measure, or through another measure that I set up to try. The measures were set to drop loads of 6.3 grl, however they both dropped loads of 6.3 to 6.7+ grains. I really cannot fathom the cause. The flakes of powder seem to be of uniform sizes.

The problem is the size of the flakes(disks), not your measure. Most will handle small flakes, spherical powders or "sticks" quite well. Larger particles (flakes/disks),e.g., Unique, don't flow or measure that easliy. Btw, the Lee powder dippers are wonderful, i.e., both fast and accurate (use with a powder scale), when you're using the larger grained powders.

Yep, it's those big flakes... with ball powder like AA#2 and 231 my dillon measure is right on the money, but with Unique, it can be as much as 0.3gr off in either direction of my intended charge. My solution is to use the can of unique I have on hand for plinking loads where accuracy/consistancy isn't a real concern and pick a load right in the middle of the range so that the deviation I get won't be unsafe. From now on tho, I will stick to ball powders for my measure.

Ruger#1

Mr Brasky and Mr Ruger, Thank you for the information. I was imagining all sorts of unusual things from the age of the powder to the incompentence of the operator. I've got a set of the Lee dippers which I shall use. Thank you again.