Re: Lost a few pieces of brass. Need advice.
Don't sweat it. I've done it and haven't noticed any changes in accuracy.
I make sure I add the new cases that I have neck turned to the same dimensions, annealed all, and the added cases are selected on the basis of weight or volume (h2o) if I want to take the time.
As for Winchester being crappy brass, what do you expect for something that costs half the price of Lapua. If you sort through it and build a couple of "Matched Sets", uniform primer pockets/flash holes, anneal, it works just fine. Also holds more powder than Lapua if you're looking for more velocity.
Winchester may be crappy but it's the best of the "crappy" offerings out there.