What is the main reason of that step, clean the outside ? clean the inside or both?

Cleans the outside to make them more accurate.

One good reason to tumble brass is to closer inspect brass for splits or cracks and possible case seperation...use crushed walnut bird litter from Pets Mart...with or w/o polish..if you use polish use non amonnia type..adding a dryer sheet in the tumbler tub will reduce alot of dust...clean brass looks better too.....

quote:

Originally posted by Bobletroutcul:
What is the main reason of that step, clean the outside ? clean the inside or both?

Cleaning brass removes "grit" that can be hard on the dies as well as the items armed_in_utah mentioned....it also is good to feed clean ammo into the chamber......but it's mostly for "pretty"

It also make them look pretty when you open the box at the range0.
Lyle

if you're shooting in a auto, shiny brass is must easier to find that is dirty stuff

quote:

Originally posted by butchloc:
if you're shooting in a auto, shiny brass is must easier to find that is dirty stuff

+1

Even so, you have to move around a bit. I've spent ages looking straight down the necks of ones base down in long grass.

It give you something to do between depriming them and reloading them. The fact that it gets clean and shiny makes you feel like you did something good and useful.

I clean brass to remove anything that could hurt my sizing dies (but I could just wipe off the bass and accomplish that). I like the brass to look nice--just psychological. I also tumble after sizing to remove the sizing lube.

I tumble before sizing and after sizing and trimming to remove the sizing lube and brass trimmings.

My reasons for cleaning inside and out are

-outside, if you use dirty brass your dies and chamber walls will eventually pay the price. Either with gunk buildup or with gouges or both.

-inside, to insure against residue buildup which will alter powder capacity.