Did I Ruin My Brass?

[Dead.Leg]

***Update: The oven was in fact on set to 400* and the brass was cooked for 20-30 minutes***

Today I was powder coating some boolits in a toaster outside at 400 degrees. About 10-20 minutes after they had finished and the toaster turned off, I decided to dry some brass before priming them so I tossed them in the toaster for a bit. When I removed the cases, they had blue coloring all the way down to the rim. I dont know how hot the cases actually got but I have read that annealing starts at 482. I dont think that they actually got hot enough to anneal the entire case but the blue coloring has my worried. Should I toss them?

Here are two pics of the same cases in different lighting. The top three are the ones that got cooked. The bottom three are good brass for reference.

267170267171

[ShooterAZ]

I have made the same mistake (400*), I ended up tossing mine. Better safe than sorry.

[tradbear55]

I would toss them and chalk it up to experience.

[Dead.Leg]

That was my thought as well. It sucks but it looks like Ill be tossing 40 pieces of brass.

[john.k]

Heated less than red hot ,annealing is minor.....the colour is dependant on time at heat as well as temp.........however ,as its a cheap/common case ,its no loss ......I f you fully anneal something that costs $3 -$5 a case ,then its different.

[Ozark mike]

The torch process of annealing gets brass hotter than that brass is extremely conductive and absorbes mor heat than youd think

[Huvius]

Speaking for myself, I wouldn't worry about it.
Looks more like discoloration of whatever was left on the case - (notice no color change at the rim recess) and as you mention, the oven was not over 400deg and was cooling from there.

Makes me wonder about factory case formation from the start.
I know most cartridge cases are made from extruded brass which, I expect, sort of forges the brass to form the case.
This forging probably makes a strong homogeneous brass from top to bottom which is annealed at the neck/shoulder to form the final case.

What about cases that are turned from brass bar stock?
They don't have the benefit of being forced into extrusion dies yet are often used for high pressure wildcat loads.
Should we worry about those?

BTW, the only case separation I've ever had in a Rook rifle was with lathe turned brass.
After that, I avoid turned brass if at all possible.

[Winger Ed.]

They're probably OK,
but if you aren't comfortable with them, throw 'em out.

[Pipefitter]

Brass does not begin to anneal until you get it to around 700*,,, load them up and shoot them

[country gent]

annealing is a combination of temp and time a cooler temp at a longer time will anneal also. The torch method heats the case quickly to 700* before the temp spreads to the base. A longer time at a lower temp will anneal but the spread down to the base will be farther and closer to the rim. How long in the oven were they? The bases were unprotected by water a holder ( heat sink) or quick time, they took the brunt of the heat along with the rest of the case. I believe Id smash the necks and trash them

[M-Tecs]

http://www.massreloading.com/annealing.html

What Are The Specifics?
Brass is annealed by heating it to a certain temperature for a certain amount of time. The higher the annealing temperature, the shorter the time required to anneal. The grain structure of the brass begins to change - indicating the start of annealing - at just under 500 degrees Fahrenheit. At 600 degrees F, brass will anneal in one hour. At 800 degrees F, brass will take only a few seconds to anneal.

Only the case necks should be annealed. If the case body or head is allowed to overheat, the case will be completely and irrevocably ruined for reloading. Also, no portion of the case should ever be allowed to reach 950 degrees F. At this temperature, over-annealing will occur, rendering the brass too soft and weak to reload.

As you can see, annealing is a balancing act - the neck must be heated (but not overheated) to the appropriate temperature for the appropriate time, while ensuring that the rest of the case does not reach a temperature that will cause it to soften as well. In addition, your process needs to be very consistent from case-to-case in order to preserve accuracy.




https://bisonballistics.com/articles/the-science-of-cartridge-brass-annealing

[Dead.Leg]

Update for the temp and time in the oven. I didnt notice before but the oven had been knocked past off and into 'Stay On' mode. With that the brass were at 400* for between 20 and 30 minutes.

[Gar10]

They should be fine, but if you don’t trust them scrap them. Ruining a firearm or injuring youseld isn’t worth it.

[country gent]

Does oven maintain set temp in stay on mode or does it "stay on" to what ever temp it can reach? 20-30 mins at 400* + I would definitely destroy it

[lar45]

For the lathe turned brass, brass bar stock can be ordered in different hardnesses. It's up to the person turning the brass into cases to know what to order.

[Texas by God]

Bite one of the good ones gently on the side of the neck with your molar. Do the same thing with one of the suspected over baked ones. If you don’t detect a dramatic difference don’t worry about it.

[303Guy]

I once left brass in the oven that I put in for drying. The oven was not hot but enough to dry the brass. Well, the next morning they had this dull appearance. I loaded some up and test fired one. The head expanded where it wasn't supported so that answered that question. I could have just tested the hardness but for some reason I didn't think of that.

[Tripplebeards]

IMO you’ll know if you wrecked them when boolit seating. I have annealed a few cases to hot that the necks squish down when trying to seat my boolit/ bullets in them. I’ve heated up brass a little to hot by accident drying in my oven after pin tumbling without issues. I anneal mine with a cordless drill. I use a socket to set my brass in and heat the neck while spinning the brass. As soon as it starts to look pink I dump my brass in a bucket of water. Like I’ve said above if I overdid it I’ll squish necks when seating bullets. I’m getting to the point that I don’t let the necks turn pink anymore so I have fewer to zero casualties now. I know I over heated as well when trim some of these cases after firing because the necks will grow quite a bit. Also when I chamfer them they are so soft that it looks like the part I tried to chamfer looks ruff like my tool snagged on the brass...or in extreme over annealing the case necks bend when chamfering...and then they get tossed. After firing these soft cases it stretches and hardens enough for me to trim and chamfer a nice smooth neck rim again.

[44magLeo]

How common a case are those? If once fired factory brass Them chuck them. If you spent a few hours making them from something else then you may want to do a bit more testing.
What those tests would be is not something I'm famililar with. A hardness test like done to lead but will a lead hardness tester be usable at brass hardness?
Leo

[mrbigsteel]

When in doubt, throw it out.