People always ask about differences in case capacity between commercial and military brass, so many don’t even think about the difference between different headstamps of commercial brass. The other day I was loading some 250 savage in Jamison brass with Hunter powder. I was 2gr under max and when I lifted the funnel off the case, powder spilled everywhere. After thinking for a bit I tried it in RP brass and had room to spare.


There is substantial difference in capacity between these two brands of brass. I decided to do a little test with Winchester Staball Match and the two different headstamps. I chose that powder because I could fit a max charge on both cases. I loaded 7 rounds with each, going up .5gr in charge weight from almost minimum to maximum. The results were as I expected but was fun to have the actual differences in actual numbers to compare.

At starting charge there was 102fps difference. Midway was 170fps difference, and at max there was 139fps difference.


Sent from my iPhone using Tapatalk