In my quest to get the best loads possible (for me, anyway) I am looking at case capacity for my .223 Rem reloads. There are a couple of websites that give case capacities re: volume of water. I just bought 100 Lapua Match cases- empty weight they are significantly heavier than the LC 07, LC 11 and .FC. I have been using. I realize internal capacity is what matters regarding weight. Some postings on the internet indicate that Lapua Match cases had less vol. using water weight measure- but I intend to weigh them myself.

SO logic tells me the less internal capacity, the more pressure, correct? So I'd need to reduce loads somewhat to attain the same results when going to a case with lesser internal capacity?

I've read here and elsewhere that when using military brass (thicker walls, less internal space) to reduce loads by 10%. I generally do not load to max weights anyway.

IS THERE A FORMULA available to tell how much reduction is needed to maintain equal pressures when various cases? In a 2007 thread here one of our members attached a link for just this thing...but the link did not work. Maybe I'm not searching with the proper words- but I am finding nothing. Not trying to be lazy- just more efficient in re-working loads. For instance, I use 25.1 GN Win. 748 behind a 50 Gn. Vmax bullet in my LC11 cases and get consistently great (less than 1/3") groups. If I do the 10% reduction thing, I'd have to start back at 2.3 / 2.4 grains?

Any help would be appreciated. THANKS!

Brian