If the Lapua cases are heavier, then you may require a load reduction but weigh a few of each and compare.
Lake City brass is also on the heavy side, so you may not find much of a difference. Changing from Winchester to Lapua is more of a significant change.
Remember that case capacity in a new case is one thing, but after it's been fired in your rifle and expands to your chamber, that is quite another.
Most people will use one load for virgin brass and another for after it has been fire formed.
Bottom line is that case weight is the final differentiator of case volume of a fire formed case.
How would you compare Winchester? I switched from LC to Winchester for another batch of 100, I added .1gr because I heard Winchester has more capacity. They fired fined, no pressure, good velocity, brass looks good. I was just checking the size of the shoulder on the new Lapua and they vary in length so they definitely need fire formed anyway. I'll have to grab some cheaper bullets to fire form with.
Can anyone comment on the difference between CCI 41s and CCI400s? I know the 41s have a harder cup but that's about it. Not sure how they react differently with the same powder charge. I also recently grabbed some Federal Gold Medal AR primers to try.
Just trying to figure out which brass and primer to use with which powder and bullet. I am working on 3 different loads for my 223 bolt gun.
75gr ELD 8208 XBR for tac PRS
80gr ELD N140 for 600y Any/Any high power
75gr BTHP Ramshot Tac for practice/fun
I've found some velocity plateaus and am testing seating depth next.
I have some other bullets to try but my time is limited. I'm wanting to use the Lapua for the High Power 80gr ELD load.
The Winchester ran great the last PRS match I shot with 75s, didn't sting losing a few cases.