Tumbling/Decapping

[Doug B.]

How do you prepare brass?  Tumble first or decap first?  Any reason that one should be done before the other? 

[Old Syko]

If not loading on a progressive I first tumble in walnut hull with enough mineral spirits to evapoprate after about 1 to 2 hours.  I then resize and decap in one operation.  The brass then goes back into a second tumbler with walnut hull and a shot of liquid car polish.  Add the polish first and allow to circulate in the media for 10 minutes or so before adding the brass.  30 minutes or so and the lube is gone and you have brass that's brighter than factory and ready to prime and charge.

If using a progressive I decap only, tumble with mineral spirits, load, then tumble the loaded ammo with polish to remove lube.

[stimpylu32]

Doug B

I have done both ways , a lot depends on just how dirty the brass is so i don't scratch my dies , the down side to sizing and de-priming first is that you must make sure that no walnut or corn cobb is stuck in the flash holes before re-priming , especially if using the Med or Fine . not a bad chore , just another step in the process .

stimpy

[davem270win]

I like nice shiny brass, so I also do the double-tumble. Right from the range into walnut hull to clean them up, then resize and decap, and into corn cob to remove lube and clean the primer pockets a little. Yes, you have to be sure no media gets stuck in the flash hole, but you should inspect your brass anyway, and it's mush easier to inspect clean, shiny brass.

[Old Syko]

The reason I switched to walnut hull from corncob media was the plugged flash hole problem.  If you use the right grind it is impossible with walnut hull.  I've run 10s of thousands of rounds this way without that first plugged hole.  If it is a concern you can always use the ceramic media used in sintered metal parts manufacturing but it tends to slightly harden the brass making it brittle too soon for my tastes.

[LaOtto222]

I tumble, then punch out the primers. I then clean the primer pockets, resize (neck or full length), reprime, powder charge, seat the bullet. All as separate operations.

[drdougrx]

Ditto for me (LaOtto's method).  I also use an RCBS Trim Case Mate (an electric machine with multiple stations for primer hole deburring, pocket cleaning, inside and outside case mouth debur, etc.)  I use corn cob with no grit or rouge and tumble for about 2 hours or so after the range and then again for about 20min to remove case lube after I reprime.