The only annealing I've ever done was during reforming .357 brass down for my old .256 Win Mag. Then, it was just the neck.

I've wondered about normal brass that might have had multiple reloads. Some sources say the brass hardens and annealing is required. In that case, how much of the case needs to be annealed? Just the neck? The whole case?

Annealing softens the neck only. Never soften the base. Could result in a split or blown case or worse. Maybe a lot worse.
I would only anneal rifle cases that are expensive or hard to get.
Last I did were .225 Winchester.
Lots of ways to do this. My favorite technique is to bore a neck size hole in a solid steel bar 3/4" square and several inches long.
Heat this block dull red with an oxy-acetelyne torch then insert the case neck in the hole.
Watch closely and you can see when the shoulder part starts to change color.
Pull the case out and drop in a bucket of cold water.

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-jwk-
US Army '72-'95

by the time a STANDARD case has hit the point where it needs to be annealed, its getting ready to come apart for other metallurgical reasons.
reasons to do it are for old, rare calibers, operating at low pressures and new brass slated for a radical reform, and then, only if you really need to avoid problems like split necks.

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it just needs more voltage

You should not ever have to anneal handgun brass and once you have to do it to your rifle brass it's time to buy new brass.

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S&W M642-2,
ATI 1911a1, 4.25"

This just came in a e mail from Sinclair. The reloading press.

(actually pretty funny as it is written by the president of the company and he talks about ordering some brass for himself.)

anyway here is the article:

The Not-So-Arcane Art of Brass Annealing | The Reloading Press

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Still Running Against the Wind

I haven't ever had the need to anneal handgun brass.

That hasn't been my experience. The need to anneal and obtain the benefit from doing so, depends a lot on how you treat your brass. There are some very good techniques available to effectively anneal brass necks. As mentioned, NEVER let the head of the case soften. The method that works well for me: annealing

The main thing is if you do decide to, is make sure you have control over what you are doing. Annealing is a time/temperature relationship.

To extend the life of valuable cases and particularly for reformed cases (ie. 30-06 to 8x57 or 7.7 Jap). I anneal the brass by dipping the neck end of the cases in my bullet casting pot (approx. 700 degrees) and dropping into water to quench. The older method of using a torch usually left the brass too soft to use. Never anneal the case head.

Good info, thanks.

Some annealing facts:

Cartridge brass AGE hardens and work-hardens (repeated cycles of expansion upon firing, and resizing back down).

Cartridge brass is softened by heating - QUENCHING accomplishes nothing, other than getting your brass wet... Air-cooling is fine for annealing cartridge brass. (Quenching as part of the annealing process comes from steel/iron, and does not transfer over to cartridge brass.)

RIFLE brass needs to be hard in the head, medium-hard in the middle (body) and medium-soft in the neck/shoulder area. Therefore, it's very important not to anneal the body and head of a rifle case. It's MUCH harder to control how far down a pistol case annealing goes. I'd bet that the factories don't anneal their pistol brass at all.

Pistol cases fail from hardening usually by longitudinal splits down the side or cracks / splits at the case mouth.

As far as pistol cases go, there's no real need to anneal. My 44 Magnum brass that has split or cracked from hardening has given 20+ loads, many of them max loads, all with full-length resizing, and they kept right on tickin' up to the end...

If you're getting mouth splits all of a sudden and there's obvious life left in the cases (like they've only been loaded 2-3 times), I'd consider trimming them back to a shorter version (like 357s trimmed back to 38 Spls.), to get more usable life out of them. I'd also double-check my bell-mouthing practices and check to see if my sizing die is over-sizing the brass.

My understanding is that the quenching in water is to stop the annealing process heat from progressing towards the case head. No softening is desired for the head. Heating the forpart of the case is all that is wanted. I've salvaged a lot of brass by this method. With many reformed cases, without annealing, good luck for one firing. Anneal and they are good for multiple loads.