Paddy,
I have found that a number 5 plastic tub works the best, the ones with a domed bottom. The number is in the recycling triangle on the bottom. Dream Whip, tub butter, and some yogurts are in these plastic tubs.
I've tried with and with out the air soft balls and don't see that much one way or the other. Others do.
The pigments in the polyester does appear to have a lot of effect on coverage. Harbor Freight's red covers well. As do several others.
I size both before and after coating. Is it necessary? Probably not, but I do it any way. Don't forget to 'bell' the case mouth or you will shave the coating.
Some/one of the powders I use leaves ash (2400) and a dry patch takes the ash out and the barrel is as clean as it was before shooting. Lt'Gun and 296/H110 don't leave ash or a noticeable amount and the barrel looks great.
I've ran 600 pulse 'PC' bullets in my AR/M4 Black and have not had a fail to do anything right. I'm still working loads and expected some fails with very light loadings. My bullet is a custom 130 grain 2R with no gas check and is a dream to load. After my morning shoot, I started my first run for accuracy. Later this afternoon, when the sun gets behind the trees, I will start on getting small groupings. For now, I'm going to have to trim that one tree that is getting into my line of site to my target stand. (I shoot over a small stream to the apposing bank.)
