I noticed some green corrosion on some loaded ammo I have in my garage on my loading bench.
I normally keep some there as I load or prep to shoot.
Most kept indoors.
I do however, have a LOT of brass in various stages of development including new cases, cleaned, shot brass, etc and loaded factory ammo and bullets.
I don't store my powder or primers there ~ that is inside in different places.

It wasn't much only a two 50-round ammo boxes.
I still had three other 50-round FMJ that werefine.
Different bullets 55fmj and 55VMax, same powder N133 and Wolf Primers.

The VMax was the worst.
The one box of FMJ was not near as corroded.
FMJ:


I pulled the bullets on a couple of both and there was corrosion in the neck and end of the projectile.




I imagine it is something I did in the loading process.
But am perplexed on why?

The Vmax was awful but is it shootable after cleaning the exterior?

Were they tumbled before they were loaded.

Yes, SS wet tumbled.
I figured it was loaded too wet, I have been using a dehydrator to dry them for a while now or I was sloppy on the case lube.
Maybe it was before I got the dehydrator.
Used Lemi Shine and Dawn.

That green fuzz is actually a corrosion product of brass or copper "rusting". So you put together "wet" cases. With that level of corrosion I suspect that you will have a squib at some point and advise that you isolate and break down every single suspected "wet" load. Because squibs in a rifle barrel are a giant PITA to get free.

In the future if you want to dry off your freshly cleaned cases I suggest that you stick them in an oven set to warm for 40 minutes to an hour. Then set them on a cookie sheet to cool down. Take note, most ovens set on warm will hold a temperature of roughly 150 degrees and that will NOT effect the temper or hardness of the brass. Keep a close eye on that cookie sheet as you bag the brass because just one drop of water means the entire lot will have to be baked for another cycle.

I wet tumble. And then I put stuff in the oven at 200° to dry it. Seems like you missed that step and the copper and brass began to decay. The green is called verdigris. And I’d suspect your tumbling uses LE I-shine an acid that will accelerate the decay of the brass or copper if not rinsed and dried..

I’d toss that brass, powder and projectiles.

Thanks, I have a dehydrator now that circulates air and heat, so I thoroughly dry them now.
I got it at Bed Bath & Beyond when they were around.
The one I have was originally for food but now Frankford Arsenal has the exact same one for brass but with their name on it.
Could have been a load before I got it.

The picture of the pulled-down case with the corrosion inside appears to show that the neck is split as well. It could have split as a result of the corrosion building up, but you might want to check around the rest of your loads, esp. if you pick up a lot of range brass.

That’s a lot of corrosion for just water. I’m thinking you may not have rinsed them well enough.

Looks like some surplus 308 ammo I got that was stored in an unheated garage for 40 years. In my instance, most was shootable after cleaning it up.

Another reason to rotate ammo. I also don’t mind keeping excess in the component form, lasts longer. Of course much depends on storage conditions.