I shoot my Garand with patina'ed brass, just because it looks cooler. patina brass like all have said, isn't bad. You will just have to make sure its not corroded. Everyone at the one range im a member of leaves their pistol rounds lay, its on the ground, no concrete. even when there was mounds of snow there brass was still on the ground. I went and collected a 5 gallon bucket (before any of the other brass rats could get there) and i have it all drying on a tarp with a fan on it. That brass will be fine.