Black soot build up on case heads

[DUSTY NOGGIN]

doesnt look like soot to me
.. im guessing something in your tumbling media . interacting with the brass

primer looks very flat to me..

if Smith worked up load with Peterson brass. that powder charge doesnt apply to the ADG brass .. no Peterson brass available ??? why the change

 

[wardog5]

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

Your primer looks kinda flat To me looks like your at or close to max pressure

 

[Coldfinger]

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.

I had it happen after a freshly blued action and bolt. The blueing transfer is onto case head after firing, still happening after 100 rounds

 

[DJ Fergus]

I believe it's coating coming off of your bolt face. I've blown Primers out in the past. You will definitely know it if gas leaks past the primer.

 

[Jakeweb09]

I believe it's coating coming off of your bolt face. I've blown Primers out in the past. You will definitely know it if gas leaks past the primer.

it's nitrite coated, is that known to come off?

 

[DJ Fergus]

it's nitrite coated, is that known to come off?

I can't say for sure but I know that metal from the bolt face itself will erode. So I would say that the nitride couldn't be and more durable than the metal itself. If your primer is leaking, it will have a lot of soot directly around the primer more so than the outside face of the brass head.

 

[BigJake91]

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.

I had something similar happen with 223. I came to a conclusion of choice of powder. And not enough powder. Starting up work loads I have only ever seen it on the low charge end of the spectrum. I am no expert. But I changed primers and cases. So I suptracted 10% Starting charge and got that on my 223s. hotter I got it went away. I always end up in the middle for cartridges like 223. But that is my experience