When comparing case capacity of PMC brass with the crimp ring to Remington and S&B there was a difference of only 1/10' th to 3/10' ths of a grain. Then again this is new production PMC ammo. Haven' t had any of the Lake City to compare although the standard belief is that the surplus has thicker case walls reducing internal capacity. Now on some of the 223 brass I have there is as much as 4 grains of difference. I would just buy the Winchester from Midway and know that your getting uniform capacities.