So, let's get the ball rolling and get to work.....
Brass Prep/Cleaning-
Getting us off the ground, we have to "work up" our brass in steps so to speak. We'll start by taking a look at our brass, we want to check her out for defective casings before we starting working it up. Check for split or mashed necks, or any other flaws in the brass. Small scratches and dings won't hurt here and a small ding or two in the case mouth isn't too big a deal. Furthermore, if we are loading for AR's, it's not uncommon to see dented case mouths. We want to check for overall condition of the brass. If you've picked brass up from the local range, be extra watchful. Discard damaged cases and stay away from severely corroded brass.
After we have looked our cases over and sorted them out, we need to look at cleaning the cases. This is especially true on range pick-up brass. We don't want to run dirt, crud and the like thru our dies. We take our brass, dump it in our tumbler and add our corn cob or walnut hull media. If using brass polish, add the media and polish and let it run for 5-10 minutes BEFORE adding the brass. It'll give the polish time to work thoroughly into the media.
Add the brass, place the cover on the tumbler and go about you're "rat killing". I like to let the brass run in the tumbler for about an hour at a minimum. That gives it ample time to clean her up pretty good, but you can let it run longer. I have, on occasion, let it run overnight.
2. Brass Prep/Trim-
When we fire a cartridge, it "grows" in the chamber of the weapon. Moreover, as we work and size the brass, it stretches, compresses, etc. One of the steps we want to take starting out is checking the length on our brass. Brass, especially new brass, needs to be trimmed to insure that it is within specification for the specific cartidge.
For our fodder here, the Sierra loading data for the .223 Remington (AR data) states our brass should be trimmed to 1.750". We use our caliper and measure the case length to determine where we are at on the brass. In the following picture, we can see our brass had "grew" a bit and needs a tad bit trimmed off.....
After we have measured all of our brass, we are gonna trim her down to spec. For this, we will use a Lyman case trimmer. The trimmer uses caliber specific pilots to center the cutter on the case mouth. We use the .22 caliber pilot here as we are trimming .223. In this process, we adjust the trimmer per the manufacturer's directions we received with the trimmer. Here we adjust, trim, measure and repeat until we reach our specified length (1.750" per the Sierra data). See the next picture for our trimmer.....
Once we have our trimmer adjusted to trim to length, we trim each piece to length. This insures that ALL our brass is the same length and within specs from our data. This will also aid in setting up our dies later. After we have her trimmed, we should be within specs.......
1.750" on the nose, this was our target length.....
3. Brass Prep/Champher & De-Burr-
After we have everything trimmed to length, we still have some work to do before we can load. When we trimmed our brass, we left a burr on both the inside and outside of the mouth of the case. We will use a champher/deburring tool for this next process. It is merely a tool, either hand turned or a powered unit that removes the burrs from the case mouth.
This is a simple hand turned tool, it does both the inside and outside of the neck.....
We take the tool, insert it into the neck and give her a few turns. We don't want to bear down, just a couple of light passes. We flip the tool over and do the outside as well, again, just a few turns is all it takes. The case mouth should be smooth both inside and out, a quick look and feel will tell us if it needs more. A quick pass with a bore brush in the neck of the brass will help clean her out prior to sizing.
We should see a smooth shiny bevel both inside and out on our case......
Now that we have our brass inspected, cleaned and trimmed, we are ready to start sizing our brass. We'll continue that in our next section on setting up our press and dies to start sizing.