Black soot build up on case heads

[Jakeweb09]

Anyone ever get it? And what causes it? I've been getting decent build up on some cases but not all. Tried multiple primers and same thing. It's happening on a 7 Saum with ADG brass and reloader 26.

 

[Tiny Tim]

Any Pictures?

 

[Jakeweb09]

Example. This is after being in the tumbler for a bit too

 

[milo-2]

Example. This is after being in the tumbler for a bit too

Unless your cases feel and look gritty coming out of your chamber, my guess is being the case heads are rougher, your media in the tumbler has dust in in it and the case heads are collecting it.

 

[Jakeweb09]

They're coming out of the chamber like this, I was just saying that it doesn't come off very well in the tumbler. Clean when chambered, black after.

 

[milo-2]

They're coming out of the chamber like this, I was just saying that it doesn't come off very well in the tumbler. Clean when chambered, black after.

Ok, that means you have gas coming back towards you, your necks and or shoulders are not sealing off. The sides of your cases should have some carbon on them too.
I would look into this right now.

 

[milo-2]

Let's see a pic of the neck of a fired case.

 

[kiwikid]

When I enlarge your photo it appears that the primer is pierced.

 

[243winxb]

Use a mag primer. Light loads & slow powder may be the cause. Use a faster burn rate of powder. Pressure is low & neck not expanding to seal? Make sure the bullets have enough neck tension. The expander should be .002" smaller than bullet diameter. This will keep the bullet from moving when the primer fires.
*Sorry about the dark text. Copied it from one of my old posts.*
What is your COL? The bullets bearing surface should be in full contact with the neck. If seating the bullet long to get close to the lands/rifling there may not be enough shank of the bullet in the case neck.

 

[Jakeweb09]

When I enlarge your photo it appears that the primer is pierced.

I've examined closely and no piercings. I believe what you're seeing is just a shiny primer with reflections of light above

 

[Jakeweb09]

As I said they had been in the tumbler about 30 min before I took any pictures of them. But here's the case neck shoulder..there is a little on the necks but the shoulders were clean

 

[Jakeweb09]

Use a mag primer. Light loads & slow powder may be the cause. Use a faster burn rate of powder. Pressure is low & neck not expanding to seal? Make sure the bullets have enough neck tension. The expander should be .002" smaller than bullet diameter. This will keep the bullet from moving when the primer fires.
*Sorry about the dark text. Copied it from one of my old posts.*
What is your COL? The bullets bearing surface should be in full contact with the neck. If seating the bullet long to get close to the lands/rifling there may not be enough shank of the bullet in the case neck.

I don't have the col off hand but it's not seated long I believe it's somewhere around 2.885 off the top of my head. And first loading they were fed 210 primers and second I tried cci250s. Neck tension was set with a mandrel on initial firing, and then set back to .001 tension with a Redding type s bushing die. I've always set neck tension to .001 in my rifles so not sure if that could be the problem. Also I'm shooting 180vlds with rl26 out of a 26 inch barrel

 

[milo-2]

My suggestion is more powder, or a faster powder, and run a minimal bump.

 

[jdyoung]

I've examined closely and no piercings. I believe what you're seeing is just a shiny primer with reflections of light above

There appear to be two strikes on that primer. one that appears normal, and a second inside the first which appears to have been made by a sharper pointed center section of the firing pin.
What does your firing pin look like ? Picture ?