Thread: See separation?

Unlike steel, brass does not harden with rapid cooling, it makes no difference if it is dropped in water or left to air cool. The only way to harden brass is by working it as in sizing it.

A few questions.
How do you anneal them?
Do you clean your brass and if so how and what additives do you use?

Never seen that happen after a only a couple firings.
One thing I notice is that the carbon on the case appears to continue past the cartridge neck and onto the shoulder. To me this would indicate that the case is getting sized too much, pushing the cartridge headspace back too far; allowing gas past the neck and onto the shoulder. (or the headspace on the rifle is too long).
If you have headspace comparators then try measuring a sized case vs a fired case. Id bet the headspace on the sized case is too shot. (meaning you should back your full length die out - or try neck sizing only)

@Tahr if you know someone with an AMP machine, it could be possible to revive this brass with an accurate anneal. I have no proof with that this would work, but it makes logical sense.

I have had that sort of cracking of the neck in .257 AI cases. It occurs when I do not anneal at all. Usually get a split down the neck and neck base.

As stated above quenching in water does not impact annealing.

My guess is not annealling far enough down the shoulder.

Originally Posted by 7mmsaum

That’s not annealing, an instant cool is Tempering which will make the brass harder/brittle

Dunno if it is temepering/hardening but I never rapidly cool my brass.

Odd to do that after a couple firing so my guess is over annealing and a host of other possible issues.



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Originally Posted by 7mmsaum

That’s not annealing, an instant cool is Tempering which will make the brass harder/brittle

Thank the stars that you're wrong. Almost had me pulling bullets there.

@Tahr do you anneal below the shoulder?

Originally Posted by outdoorlad

@Tahr do you anneal below the shoulder?

No. I pretty much just do the neck and some shoulder.

I "anneal" using my gas stove (single burner camping thing) and heat the neck holding the base of the case and twirling it. When I feel the heat in my fingers I dunk the case in water.

My guess is under rather than over annealing

@Tahr I would suggest that your cases aren't being annealed enough. Unless you have hands of steel there is no way that you can get the necks hot enough and still hold onto the case base. At one point I touched the base of a 6.5-284 case straight out of my AMP annealer and it instantly burnt my finger tip.

If it is under annealed, it is pretty shit brass to do work harden within a couple firings to cause that seperation.
It has to be a combination of things.
Even before the annealing craze took on you could get 5 or 6 loads out of a warm load case with most brands of brass and I don't recall seening the neck separate like those above.



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Not far enough annealing past shoulder, about 5mm needed otherwise you had a hard brass to soft brass junction at neck and shoulder junction which is most likely the highest stretching/stress region on the cartridge when fired and causing case not expand uniformly in this region.

black stuff - just carbon as stated earlier, can darken more with gas annealing

Rapid cooling of brass is safe as houses and does not harden it.

One can tell if you over annealed brass with gas, first you can see the flame slightly change colour as the surface zinc in the brass burns out of the copper, also the more than usual shinny tin look to brass once annealed - not the usual annealed colour. Anyway I have fired over annealed brass as fouler shots before range shooting and never had a case separate nor any other problems apart from maybe a dented shoulder when seating projectile (but they still fire form out and case reharden with use)

Have these cases been heck turned?

I've been getting split necks upon 1st firing of my norma brass, maybe 1 in 3. 300 saum necked down. 62grains of 2213sc with a 140vld . Real mild, accurate load. I wouldnt have thought they would need annealing or anything from new? Any reason why this would be happening?