Precision Hand Loading For Long Range-Chapter One: Brass Sort & Prep
Now wipe off the case and chamber the empty case in the rifle and see how the bolt feels as it closes. Was there any resistance? You want to bump the shoulder of the case back just enough that you’re at the borderline of having/not having a teeny bit of resistance in closing the bolt on the case. Now you have your resizing die set as well as you can until the proper tool arrives in the mail.
Brass work hardens. Shooting it, resizing it, tumbling it- it all hardens it. Which means some will be harder/stronger on their grip of the bullet than others and our consistency in everything we are trying to achieve went right out of the window. This example is known as "neck tension" or the amount of grip of the case neck on the bullet. Therefore we need to anneal our brass cases every 3 firings at least. I anneal mine every 2. You only anneal the neck and shoulder, NOT THE HEAD! There are fancy case annealing machines, but I don't have that kind of luxury. Here's what I do:
Purchase some 650 degree rated Tempilaq. Tempilaq basically looks like an oversized bottle of fingernail polish.
It comes in heat grades. We used it in machine shops for various tasks. You basically paint a stripe on your metal and let it dry. Apply heat and when it gets to the temperature you want the Tempilaq liquefies and the color (yellow) disappears.
I paint a stripe INSIDE the mouth of my cases.
After it dries I hold the head of the case in my bare fingers and turn the mouth of the case in the flame of a propane torch. When my yellow paint of the 650 degree Tempilaq disappears, I drop the case in a bucket of water. Once all the cases are processed, we now have soft case mouths that will be uniform in neck tension on the bullet after they are loaded.
A word of caution: you never want the head of the case (the part that has writing on it) to get so hot you can't hold it. If you soften the head of the case you have created a very dangerous as well as troublesome situation. At the very least, you shoot the case (even a light load) and the primer falls out and it goes on from there with far greater personal risk/danger.
And while we are babying our brass, I do what many benchrest shooters have switched to: I use an ultrasonic cleaner to clean my brass. Vibratory tumblers only "prettify" brass. They do not clean the inside, the flash hole or the primer pocket. I do not care if the outside of my brass is shiny. As a long range shooter I need the inside, the flash hole and the primer pocket to be clean in the name of uniform combustion and burn, shot to shot. Also, all the rattling together of cases in the vibrator peens the cases together, hardening them all the more (although minimally.)
I suggest you purchase an ultrasonic cleaner on the cheap from Harbor Freight. Throw in your resized/deprimed cases. Cover the cases with distilled water. Then add 1 tablespoon of dish detergent as well as 3-6 tbsp of your favorite liquid brass cleaner - Birchwood-Casey, Lyman Turbo, etc. - any of the liquid products intended to be added into vibratory tumbling media.
Run the ultrasonic cleaner 20 minutes to an hour depending on the size and number of cases until they are totally clean on the inside and the primer pockets are all at least 95% clean. Rinse in bucket of about 5 gallons of distilled water and shake off. After they air dry or you hairdryer them, you’re good to go. Tap water contains substances that can cause cartridge brass to oxidize. Stay with distilled.
[Note: After you clean your brass with your preferred manner, if you used Tempilaq to anneal them, you may need to use a bore brush to clean the burned tempilaq out of the case mouths. Make sure your case mouths are always clean in the name of consistent neck tension.]
First, we'll continue by sorting all brass by brand. Then I sort it by weight. Everybody talks about Lapua & other premium brass being the best, but Winchester brass is at least 96% as good (and cheaper!)
Sort all your best brass cases into at least 2-grain lots. That is to say all of the cases in each batch of cases weigh within 2 grains of each other. This lets you know each case has about the same brass content. This tells us they are of the same average dimensions, which means we have the same sized combustion chambers case to case, giving us consistent muzzle velocity (MV) shot to shot.
Uniforming & Deburring the Flash Hole
Uniform all the primer pockets. Here's a dirty, uneven once-fired primer pocket:
<Previous | Home | Next Page >
All times are GMT -5. The time now is 01:41 AM.