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Gunsmithing What is the purpose of annealing casings?

Elderinjun

Private
Minuteman
Aug 19, 2019
11
1
I am new to reloading and am looking into making 300 blackout casings from 5.56 casings and I tried to do some research on the topic but as all things of this nature I got many different answers to the same question. Some people say that i need to anneal my casings while others never even mention it. I was wondering what the purpose of annealing a casing was and if it was necessary for the casing. Also I'm new to the whole forum scene and don't know if this is the proper place to post this.
 
When you fire a cartridge it hardens the brass case. Annealing softens the metal and gives a more consistent neck tension. When necking up (like you want to do with your 5.56-.30can) it stresses the case less if you anneal first.

I anneal everything, but I have read Litz' test results, and I don't believe it is at all critical for the kind of shooting most of us here do. An annealer is a piece of equipment you buy when you have everything else, and are still chasing precision.
 
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Work hardening of brass happens at least as much during the sizing process as it does when firing. If you have reloaded commercial brass more than 5 or 6 times without annealing you have probably experienced neck splits. Annealing every 2 or 3 loadings helps prolong that brass life. The added benefit is a more consistent neck tension over the brass' life.
 
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Grab a wire coat hanger. Bend it back and forth. Wire gets hot, becomes stiff, and eventually snaps in half.

That is called cold forming or work hardening.

Brass is no different. Everytime you fire, size, and load, you are work hardening the neck portion of the cartridge. This also has a consequence to accuracy. The neck tension will start to vary and this alters the release tension when fired. You'll see a larger SD on the chronograph and that leads to vertical in a shot plot when stretching north of 600 yards. It gets worse the farther out you go.

Annealing cases (properly) solves these issues. It will soften the necks to where they are malleable again. Promoting longer brass life.
SD's will settle down and accuracy will be more consistent.

That's why its done.
 
Seriously not worth the time or effort to cut down 556 and make your own 300 blk brass yet alone anneal it all lol.

Just buy new or once fired 300 blk brass and lock n load
 
Grab a wire coat hanger. Bend it back and forth. Wire gets hot, becomes stiff, and eventually snaps in half.
That is called cold forming or work hardening.

Without a doubt, that is the best laymans explanation I have ever heard.
 
1 to keep them brass malleable so it can expand under fire and compress during sizing without inducing stress so you can get more loadings out of it.
Also helps to keep consistent neck tension throughout the life of the brass
 
I was getting split necks after 3 or 4 firings in my 300wm using Winchester brass, once I started annealing it easily got me 2- 3 more cycles of life out of my brass.
 
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Ok!

This thread is evolving in a positive fashion.

That’s some high quality equipment right there!
 
Build this and you have an annealer that will also serve as a jet engine.



 
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