I made my first brass 410 shell this weekend and did not even blow up the old Marlin 60G!
The brass is 9.3x74R, scored 4 of them. They do have a tiny bit of brass rust, but this was the worst and it held up. The first photo is after fire forming with 10 grains of Unique and a case full of Malt-O-Meal. The second shows the original case and the case after being fired with 16 grains of 2400 and 300 grains of #4.
Why??? Because I can and they can be loaded with nothing more than a pair of punches, one to remove the primer and one to pack wads.
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