velocity diference with regards to case capacity

[davewilson]

if you have 2 cases that hold 1 grain difference in total amount of powder, but you put the same amount of powder in each one. all other things being equal,will it make any difference in the velocity? i understand this is why we separate the cases, but has anyone actually tested this to see if it makes a difference?

 

[goodgrouper]

The smaller the case, the bigger difference 1 grain would be. But even on cases as large as the ultra mags, if you are running an upper end node that is very near maximum pressures that the case will handle, 1 grain might just be enough to put you over the top and ruin accuracy or become dangerous.