emily2000
I was given three five gallon buckets of once fired .223/5.56 brass fired by our local police departments. I first cleaned the brass with a home made liquid case cleaner from the link below.
Homemade Firearm Cleaners & Lubricants
A solution of 1 quart of water, 1 cup white vinegar, 1/2 cup lemon juice, 1/4 cup laundry or dishwashing detergent, 1/8 cup salt.
http://www.frfrogspad.com/homemade.htm
The method above needed more "bling" so I purchased the STM tumbler and was very happy with the results.
My advice, sort your brass by headstamps and clean with a standard size tumbler. Yes it will take longer but I'm guessing your not shooting as much as Jerry Miculek.
After I sorted my brass into two groups, I use the Lake City brass in my AR15 A2 HBAR with accuracy loads and the rest for practice ammo in my AR15 carbine.
Don't mind what other people say here, when I was given my three gallon buckets of brass I thought it was a early Christmas. And in my opinion anyone using Lapua brass in any firearm like a AR15 that throw perfectly good brass away and makes you go looking for it is out of his gourd.
Below just some of the "free" once fired .223/5.56 brass that was given to me, which was much cheaper than buying once fired brass for my AR15 rifles. So keep smiling with your mountain of free brass and remember this in this forum....."Illegitimi non carborundum".
In closing I'm a cheap bastard and the expense of buying even a small cement mixer and the required large quantity of stainless steel pins would cost far too much for any savings with your quantity of brass. So I would just sort the brass into smaller groups by headstamp and work on it on rainy days.