Prettiest brass

[helotaxi]

primer pockets should be cleaned also.

Seen too much evidence that this is false to place any stock in the value of cleaning primer pockets... 

Banging around for hours on end in a tumbler just dings and hardens you necks.

...and you're kidding, right?  I'll believe it when I see actual scientific testing that supports it.  The forces involved are so miniscule that the brass isn't even deflected.  No deflection, no work hardening.

[Buckskin]

primer pockets should be cleaned also.

Seen too much evidence that this is false to place any stock in the value of cleaning primer pockets... 

Banging around for hours on end in a tumbler just dings and hardens you necks.

...and you're kidding, right?  I'll believe it when I see actual scientific testing that supports it.  The forces involved are so miniscule that the brass isn't even deflected.  No deflection, no work hardening.

 
This is from Vamint Al's Reloading page, a guy who know a little bit about the subject....  But hey, you know better right...
 
 

NECK MOUTH.... On the left is a brand new 243 Win brass and you can see the rolled over edges of the mouth do to the hammering that occurs in the polishing process. Also the hammered area is work hardened and locally is no longer in the annealed state. If you have ever noticed a tiny ring of gilding metal scraped off when you seat a bullet, it is this hard rolled over ring of brass that does the scraping. Even after inside and outside chamfering, there is still a burr left at the edge of the cut surface.
On the right is one of my 23/40 brass cases after the neck has been trimmed square and fired a number of times. I gave it about 30 revolutions in the Steel Wool Spinner to show how smooth the neck mouth is. With the smooth annealed neck and no rolled over burr, bullets seat very smoothly without scraping gilding metal of the bullet.
 
.... Smooth and uniform case mouths are very important in producing accurate reloads. Therefore, I don't polish my carefully prepared brass in a tumbler. During polishing, the case mouths are hammered against the other cases in the tumbler. The hammering rolls over a small lip or burr on the ID and OD of each case mouth. This peening process also locally work hardens the brass. These tiny rolled-over rings of brass at the case mouths are harder than the rest of the annealed neck. These rings and tiny peen marks are very obvious on new brass. If you look at your nice shiny cleaned cases out of the tumbler, you will see the battered case mouths!
 
http://www.varmintal.com/arelo.htm
 
 

[helotaxi]

I've read Varmint Al's pages extensively, and while I respect his opinion, that's all it is in this case.  Unless he's using a paint shaker and gravel to tumble the brass, there's simply no "hammering" going on in the tumbler.  It's actually a very gentle process.  Trimming brass, chamfering and deburring will do more to work harden the case mouth than tumbling with a vibratory case tumbler using corn cob or walnut shell.

Until someone shows the results of a hardness test and magnified images before and after, I'm not buying it.

[Forsberg]

Salt, vinegar, lime juice doesn't sound to good for the brass. Must be like mercuric priming  used to be for barrels and chambers. Brasso, Flitz, jeweler's rouge not good for barrel life. Work hardening necks and raising burrs on case mouths? I'm going to have to see some Rockwell numbers before I buy that.
If I just want to clean the outside of the case I'll stick with toilet paper. If I need to clean inside and out and the primer pockets as well I'll use SS media and a tumbler. Clean case not only look professional but function better.

[Buckskin]

Until someone shows the results of a hardness test and magnified images before and after, I'm not buying it.

Well maybe you missed the magnified images above.  Do not have any hardness tests for you, although I bet Al would be willing to do some for you or at least explain his theory if you email him...  Pretty easy to see the peening being done, I've done it. Put half your brass in your tumbler, half not tumbled and look with a magnifying glass. If it's peened, it's worked, if it's worked, it's hardened.
Here is another article that mentions it and there are many discussions on the subject as well if you do a search.
http://www.realguns.com/Commentary/comar46.htm
 
A clean case is a necessity, but that doesn't mean it needs to be polished. That is all for show. Which is fine, I use a little bit of Flitz on my fishished rounds from time to time. Not sure how it would get in the barrel though... Once in a while if the cases are really dirty I will wash them. But I'm pretty much done with tumbling. 

[helotaxi]

Until someone shows the results of a hardness test and magnified images before and after, I'm not buying it.

Well maybe you missed the magnified images above. 

Did you read the captions that go with them?  The one that's all beat up is a brand new case, not one out of the tumbler.  Blame packaging and transport for that, not the tumbler.  My cases come out of the tumbler with the clean, shiny edge from the the trim/chamfer/deburr still perfectly intact.

[wncchester]

"Does pretty brass shoot any better?"
 
Certainly, I thought all web readers knew that!   Just as pretty cars go faster and get better gas mileage, pretty rifles shoot much better and reach further, pretty women are nicer and better cooks, etc.  And pride for trivia surely has some kind of value, at least for those who are impressed with meaningless glitter.
 
The  idea that cases are 'battered' and 'work hardened'  by tumbling is amusing.

[Buckskin]

Well I'm glad your amused... 
 
I was sitting at my bench last night and thought I would play around a little. So I took two old pieces of 300 rum brass and chamfered them and put my cleanup spinner on them until they were perfect. Took one of them and lightly tapped on it with the side of the other piece of brass, and I mean lightly, like 1" apart and just let gravity do the rest.  Much less contact than what would occur during hours of tumbling. Then I compared them under a magnifying glass, massive difference between the two. Now I figured 300 RUM is a pretty big piece of brass so I did the same with 223 brass with the same results. 
 
 
Also looked through my brass and found a bag of 30-30 brass that was cleaned and sized but not chamfered, necks looked just like what is pictured above. Brass is very soft, especially the necks so makes sense that the edge would get beat up during polishing.  Now is it ruined no, will it affect anything after chamfering, probably not.  But the damage is there and if it's worked it's hardened some even if in that tiny little spot....  Try it yourself.