One can clearly see, hear, and feel significant difference in shooting this same 5,000 psi #7625 load in a 12 gauge vs, the 10 gugewith sleeves. My shoting partner coud readily see the slower shot string from the 10 gauge, but not from the 12.

By the way, the IMR loading manual lists 12 gauge loads with #7625 down to 4,200 psi.

Let me re-ask this question another way....What is the "volume difference percentage" between a 10 gauge 30" barrel, and a 12 gauge 30" barrel?

Thanks.

Jerry