Brass discoloration

[dtwalters]

Does anyone have an explanation as to why the two outer shells are discolored? They are all Winchester 38 Special shells that I have reloaded multiple times. After firing, they are decapped, wet tumbled in Brass Juice and stainless steel pins for about an hour, rinsed and then left to sit overnight in a toaster oven that was pre-heated to 250˚F for 10 minutes and then turned off. The other 998 turn out just like the center one. Odd!
(This post has been edited for clarity.)

 

[bullseye308]

Not sure, but maybe number your cylinder and see if it only happens with certain chambers. Could be a couple need honing.

 

[dtwalters]

bullseye308,

Well, the other 998 of them aren't discolored, so I doubt that it is a problem with a cylinder. Thanks for your reply!

 

[WeekendReloader]

Are they discolored before putting them in the toaster oven?

I'm guessing that the heating elements in the toaster oven cause hot spots in areas and are affecting some of the brass.

Also, different head stamps may use different alloys of brass that are affected differently by the heat.

 

[Rule3]

To hot, to long, to much magic juice
Disturbance in the Force
Brass variation

No worries

 

[dtwalters]

WeekendReloader,

The lot of 1000 that these came from are all Winchester. They have been discolored like that for a long time, even before I started using the toaster oven. Some of the lot were originally once fired (by me), others were given to me and still others were range pick up. I have no way of knowing which are which. Thanks for the reply!

 

[dtwalters]

Disturbance in the Force

Most likely. Thanks for the reply!

 

[Charlie98]

Brass variation

I have some brass that discolors more than others... I put it down to the brass mix.

Question for the OP: What headstamp brass is that? (I have an educated guess, but I'll wait for your reply. )

 

[Lennyjoe]

Baked in an oven? Now that’s meticulous

 

[docbrown]

Did you perhaps have a couple of larger cases mixed in there when you tumbled them? Sometimes if I miss a 40 S&W case when tumbling 357 cases, the 357 case slides inside the 40 S&W case and gets stuck there and I see something similar to what is in the picture. Part of the case does not get tumbled.

 

[reddog81]

I'm more worried why you think the oven needs to be preheated... Do you think the brass will come out under-cooked and runny if not at full temp the whole time?

 

[docbrown]

I'm more worried why you think the oven needs to be preheated... Do you think the brass will come out under-cooked and runny if not at full temp the whole time?

Well, you do want the golden brown crust, don't you?

 

[.38 Special]

I've had some that ended up looking like the one on the left. They were stored in foam trays and the bases were exposed to I don't know what. Maybe just years of oxygen. Whatever it was, they worked just fine, even if they never came perfectly clean.

The one on the right does look like heat discoloration, and I'd be worried about it after putting it into the oven. It is odd that it is the only one out of a thousand to look like that, and it's probably fine (it's probably not even heat discoloration) but I've gotten pretty conservative about handloading and would probably toss it, in your shoes.

 

[dtwalters]

What headstamp brass is that?)

Winchester

 

[dtwalters]

Did you perhaps have a couple of larger cases mixed in there when you tumbled them? Sometimes if I miss a 40 S&W case when tumbling 357 cases, the 357 case slides inside the 40 S&W case and gets stuck there and I see something similar to what is in the picture. Part of the case does not get tumbled.

They have been tumbled over and over, 38 special's only. Thanks for the reply!

 

[dtwalters]

I'm more worried why you think the oven needs to be preheated... Do you think the brass will come out under-cooked and runny if not at full temp the whole time?

I heat up the oven for ten minutes and turn it off, then I put the brass in. I'm trying not to let the brass get too hot. Then I leave it in there overnight.

 

[GeoDudeFlorida]

I'm more worried why you think the oven needs to be preheated... Do you think the brass will come out under-cooked and runny if not at full temp the whole time?

WARNING: Loading raw or undercooked shell casings may increase your risk of flinching.

 

[dtwalters]

Baked in an oven? Now that’s meticulous

I'm CDO.(OCD alphabetized)

 

[GeoDudeFlorida]

I'm CDO.(OCD alphabetized)

No way to know for sure without careful experimentation but, my best guess from a chemical point of view is, those spots are where slightly larger volumes of water settled in the cases when they were laid out for drying in the oven and the temperature gradations from the water effervescing (not hot enough to be steam, not cold enough to remain liquid) in those spots caused discoloration. Steel does the same thing which is why you see rainbow colors on stainless steel cookware left on a hot burner. Until you wash it with a steel pad and then it's gone. Wipe those cases down with a 000 bronze pad and see if they don't shine up to match the rest.

 

[tightgroup tiger]

I can't tell you what did that to the case but I think @.38 Special is probably the closest to the right answer.

I left these under the inferred heater over night by mistake at 338 degrees. What was curious was the mouth was what turned color first, suppose it's the thinnest. It didn't seem to hurt them, I'm still shooting them once a week.
anyways, I doubt your toaster over at 250 for 10 minutes had anything to do with it. By the way the blue never did all polish off these. Some of them still have some color to them.

 

[Charlie98]

Winchester

That was my second guess... Starline being my first guess. My Starline brass discolors quicker and more significantly than any other brand brass I have, Winchester, for some reason, tends to spot. Weird. I dry tumble, so it's nothing to do with a solution, but I do use Dillon polish, that can tend to cause age tarnish if overused. Just my experience.

Also, and this is something new... some powders tend to stain brass... I've had weird staining on my 9mm cases using W244 recently.

 

[GeoDudeFlorida]

That was my second guess... Starline being my first guess. My Starline brass discolors quicker and more significantly than any other brand brass I have, Winchester, for some reason, tends to spot. Weird. I dry tumble, so it's nothing to do with a solution, but I do use Dillon polish, that can tend to cause age tarnish if overused. Just my experience.

Also, and this is something new... some powders tend to stain brass... I've had weird staining on my 9mm cases using W244 recently.

Yup. TiteGroup. Stained about one in ten PPU .357Mag cases I loaded up for plinking loads (Hornady Frontier Lead 158gr. SWC-HP over 4.7gr. of TiteGroup). It looks like they've spent a decade in a leather bandolier but they're pretty new brass. I tossed them and didn't bother taking pictures figuring they didn't sound right. Pinging them gave more of a dull chime than a ring.

 

[FROGO207]

If those happened to be laying in the mud or water for a while. The zinc has leached out of the surface on the one at the right. Notice the pink hue on that case---thats copper. Have had some that this happened to. They were probably in the pile you were gifted and who knows how they were stored/treated before you got them.
Theory is they were left in a styro box insert and found upside down on a puddle or such some time later.

 

[dtwalters]

my best guess from a chemical point of view is, those spots are where slightly larger volumes of water settled in the cases when they were laid out for drying in the oven and the temperature gradations from the water effervescing

So...I've color case hardened them!!!

 

[dtwalters]

They were probably in the pile you were gifted and who knows how they were stored/treated before you got them.

Quite possibly.