Just posted this over at 6mmbr, but for those that don't frequent that site, here are my findings.
Today I weight sorted some .284 Winchester brass. Needless to say I got a shocking result. I know there has been some discussion as to what brass guys are using in .284 Winchesters; either "straight" .284Win Win brand or necked-up 6.5x284 Lapua (oh the irony). I've read that Jerry Tierney extensively tested both Win and Lapua brass and found "Win brass shot as accurately as the Lapua brass". I know that the Win stuff will need to be annealed though. Anyway, here is the breakdown.
Started with 200 brass. Two bags of 50 with the same lot#, and 2 other bags of 50 with the same lot# but different from the first. I guess that was a complicated way of saying two groups of 100 with different lot#'s.
All brass was fully prepped. Flash holes deburred, primer pockets uniformed, full length sized, trimmed, necks turned, necks deburred, and inside of necks polished.
12 brass were immediately culled for random things like crimps and off center flash holes.
188 brass were weight sorted into groups with one grain increments. For example, group "205" weighed anywhere from 205.0gn to 205.9gn.
Just wanted to pass on my results. I thought someone would find this interesting. Anybody have anything to add? Anybody find similar results? Anybody using annealed Win brass? How do Lapua compare to Win in terms of weight uniformity?
That is more or less what I found with Winchester brass in 308. I managed to get 4 usable groups of out of three hundred cases (not counting the ones I threw away).
As AJ suggests, weight sorting alone will not do the entire job. It helps tremendously, but there will still be individual cases that produce fliers at long range. Immediately throw away any piece that does not shoot to group. After 1 or 2 firings you will have some very uniform brass.
I have been doing all of my brass sorting by shooting them.I gave up on weighing,and filling them up with water.I keep all the one's that group together in a pile,the one's that were 1/2moa off(I mark them "high or "low"),and put the complete fliers in another pile.Anytime I go out and shoot,I just keep track of every shot,and mark the brass with a marker.In my opinion,this is the best way to sort brass.
I weight sort AFTER brass prep.
Doing things like neck turning, uniforming flash holes, trimming etc. removes brass and therefore weight. The idea is to have brass that have exactly the same outside dimensions, then any variation in weight has to be variances inside the case, and therefore differences in internal volume.
I personally don't think, and can't for that matter, measure water accurately enough to use water as an accurate means of measuring internal volume. Sounds great in theory, but difficult to accomplish in reality.
In terms of work, I estimate I spend an hour on each piece of brass from start to finish. Things like turning and polishing necks are time consuming to say the least.