White residue in primer pocket?

[coloradokevin]

I've never seen this before, but I was decapping some of my .308 Win brass today, and found that the primer pocket on one of my pieces of brass had white residue in the primer pocket, rather than the black residue we're all used to seeing?

What could have caused this, and what does it mean?


NOTE: this is brass that I've had since it was factory new Federal Gold Medal Match ammo a couple of years ago, and it has been reloaded a few times by me, using Winchester primers that are less than five years old (in other words, this wasn't some old Milsurp ammo with corrosive primers).

 

[FROGO207]

I have seen some factory new PMC brass ammo in handgun calibers have a white film inside the case as well as the primer pocket after firing. Always assumed that it was the primer/propellant combo that they used. Never heard of it happening with your component combo however. And just one round as well makes me wonder if you had something in the brass from when it was cleaned and you just discovered it when decapping them. Could you have a stray piece of brass there that was not yours that you picked up?

 

[coloradokevin]

No, this was definitely all my brass. It's for a precision rifle, so I am pretty meticulous about my loading and tracking of the brass. I can tell you exactly how it was loaded on each loading since it was new!

The powder I used was Varget, which has proven to be pretty consistent in my experience.

I do shoot in a variety of different field conditions though. Could this have possibly been caused by some moisture getting down into this case?

Hmmm...

 

[rcmodel]

Yes.

I have seen it in the past.

I think it is moisture breaking down the ash left from the primer residue.

At any rate, it seems to be nothing serious to worry about.
It cleans out easier then the hard black crud you usually find in primer pockets!

So, it must be a good thing!

rc

 

[coloradokevin]

Sounds good. Thanks for the help!

 

[ironworkerwill]

Moisture, I've noticed, will cause the ignited primer residue to become white. I considered it lead oxidation.

 

[JoelR9801]

I've gotten white residue from the case polish that I put in my media. Now I add it before the shells and let it run for a few minutes 1st.

 

[joustin]

Ironworkerwill is thinking the same as I did, lead oxidation probably