doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Annealing brass

In an ongoing quest to learn more about converting 9.3 X 74R brass to 3" .410 brass I am wanting some info about annealing the top third of the case. It seems to be pretty much a given that the top third of the case should be annealed before allowing fire forming to expand the neck to .410 chamber dims. After reading up on doing it, and seeing everything used from a $1300 electric induction annealer to a handheld propane torch, I'm left with a question about the process. I see conflicting methods concerning the cooling of the brass after the heating. Some dunk them individually, and immediately, in water. Benchrest shooters, who use the expensive annealer I mentioned above, seem to let the case cool on it's own (in the videos I watched).

I've always been told that to properly anneal an action, or any other piece of steel, it should cool as slowly as possible. Some used to even pack them in lime to extend the cooling down period. Is brass different? If the idea is to relieve internal stresses in the case shoulder and neck, and result in maximum ductility, wouldn't a slower cool down be better than a quick dunk in water?

Brass is not steel, so you can ignore that. But quenching brass is not needed and most competition shooters allow them to air cool. But we are just barely heading them. For this, the cooling method will not be anywhere near as important as how much they are heated.

I built my own annealing machine which allows me to regulate heating fairly precisely. If used after every firing, then minimal annealing is desired and the brass barely gets a blue color blush before it is "done". In your case, a bit more annealing may be desirable, so you may opt for a hint of red in a dark room, but just at the neck. If you really want to push that hard, then perhaps the water quench would be advantageous because it will keep the heat from running down the case into the head region.

When I was into shooting the obscure .41 Swiss out of the old Veterlli rifles I made all my rounds from .348 Winchester. It’s not the quench that’s so important as how hot you get your brass. Heat just at the neck and shoulders enough to get a color change, blueish. You can dunk them or let them air cool. I assume you won’t be full length resizing.

Stan,
I think this is the color you may want to try.
Personally, I don’t think the temp range is highly critical unless you just go way overboard.

Ken

Used to do lots of NRA hi-power and later F-class shooting. I just always did the heat with torch and dunk method. I do seem to recall a reasonably priced anealing machine being available a few years ago, much less than the $1300 you mentioned. I'll see if I can find it again.

https://www.scheels.com/p/annealeez-gen-3-brass-annealing-machine/42100030405.html


$275



This is the one everybody was using.

Turn the sound off and this video is so relaxing to watch!!

Stan,
To get the results you are looking for, you are going to have to anneal the cases almost to the head. Note that the "almost" is very important, you don't want to soften the case head. A cousin of mine is making cases (65mm long) for a double rifle, from 9.3x74R. At first, he tried some 7x65R cases (I had previously recommended these on this board for similar rifles), but after trying every procedure we knew, he was unable to expand the 7mm necks to the necessary diameter without almost 100% of the necks splitting. The 9.3 necks didn't exhibit unacceptable losses. He did, however, have to fireform them several(3or4) times, progressively annealing each time, before the bodies completely expanded. After the initial fireforming he did the rest while testing loads, so it was not an unacceptably long process. The final result is nice looking cases. The annealing you need to do is for an entirely different purpose than the ones shown above.
Mike

The reason for quenching brass is so you don't have to wait around for 10 minutes for it to cool down before handling. The end result is the same either way.

I seem to recall reading many years ago that a way to do this by hand, and keep the case head from annealing is to put water in a large rectangular cooking sheet with raised edges, deep enough that the case can be stood up with the head in the water, then heat with a torch going round and round. Then, when the case is the right color you just tip it over into the pan of water.

I was afraid that the quick cool off by the water would defeat the reason for annealing, to a degree. I'm certain this is the case with iron, but with brass, evidently not.

Thanks for the helpful replies.