I tumble my brass, and on rare occasion tumble finished ammo (not for shine, but to clean excess lube). While I tumble I rarely tumble to a high polish with the exception of 2 cartridges; 45 ACP and 30-06. Shiny brass is easier to find in the dirt, rocks, trash at the "range" where i shoot my 1911s and Garand...

FWIW, I reloaded for 12 years before I tumbled any brass. All I did was wipe my cases with a solvent dampened rag as I inspected them. Nope, no scratched dies, and yep, I could spot any defects. All my ammo functioned perfectly and was fairly accurate...