682Shooter said:
Am I doing something wrong?
No.
The best I have been able to accomplish with the MEC has been about ±0.5 gr at the extremes, although most of them are better than that. I have no explanation for the 20g "outlier". I surmise there's a reason, but I don't know what it could be (see * below though).
Strive to use consistent strokes with consistent speed: smooth on the downstroke, smooth on the upstroke. That will help to minimize power drop variation as well as differences in primers dropping into place.
I use both a MEC 9000G and an Auto-Mate. An Auto-Mate obviously helps with consistent powder drops and everything else. Every stroke is identical whereas you might hesitate pushing the handle down if one of the stages gets hung up a bit. For example, a primer that's harder than usual to dislodge or insert would get your attention whereas an Auto-Mate just powers through.
Thank you so much for you imput. The 20gn is typically the very first shell in a series.
Out of curiosity I also weighed every single powder drop as the bottle emptied from about half full, all the way until the only powder remaining in the bottle was in its neck. The usual variations never changed. Am I suggesting you ignore MEC's "minimum powder level" printed on the bottle? Absolutely not. I encourage you to do your own experimentation though, and I wouldn't make it a habit. But I've done it. Absolutely nothing special happens below the bottle's minimum powder level all the way to empty, at least with Extra-Lite.
I don't use a powder baffle either. If you come across one and want to try it, I suppose it wouldn't hurt.
* Once, and only once, I noticed a fairly large glob of white "stuff" become visible in the powder bottle as its level dropped. I emptied the powder into a pan and discovered that contaminant resembled white adhesive often used to seal corrugated cardboard boxes. It was dry, I picked it out, poured the powder back into the bottle and continued without incident.
It did cause me to become more observant as I pour powder from the keg into the bottle though. Maybe I should have kept that glob and contacted Alliant about it, but I shrugged it off.