Im not a BR shooter but this is a varmint rifle and i am loading for as much accuracy as possible.
If that's the case, I'd suggest you toss the Winchester brass and get 100 pieces of Lapua brass... it's the best there is and can typically be reloaded 3-5 times more than lower grade brass.
In a 200 count, raw lot, the total
deviation was less than 2.0 grains. Flash holes are .078" with no measureable deviation. Case length variation was less than .003".
Yeah... it's around a buck a case, but IMO, well worth it if what you say is true.