Soot on cases

This is the NOE225-55 FN OVER H335.
An 8 case ladder test. 17.5, 18.0,18.5,19,19.5,20,20.5,21
All were GC

All cycle fine in a DPMS AR15. .223/5.56

Note the soot at the base on #2,6,7,8

What caused this?

I have 2 sweet spots for more tests-
17.5-18
20-20.5

Joe

Case necks did not expand to obturate the chamber, anneal necks of brass

^^^^ Agree 100% each and every one of them should have generated pressure to seal the chamber and maybe soot the necks
a little.

Calamity Jake

NRA Life Member
SASS 15704
Shoot straight, keepem in the ten ring.

I'm prolly wrong, but around the base? Case mouth yes, base no. Pull your carrier and check your gas rings on the bolt, make sure they are not lined up. I'd like to see a shot of the cartridges out of the case carrier to be sure but that's my take. Was there excessive carbon on the bolt face as well? From the pic's the case mouths don't seem to be too carboned up.

GSSF RSO
NRA RSO
DU

"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf."
George Orwell

These are the times that try men's souls.
Thomas Payne

I am new to the AR platform but the BCG DOESN'T look really look carbon to me. Those cases do have a tiny amount of soot on the neck and mouth area.

Here is BCG pic

Jal5,

: What do the primers look like? Are the primer pockets loose? Primers punctured?
How old is your powder? The AR is a dirty shooting system compared to a bolt, or
piston, but not that dirty.

Jack....

Primers look fine. They were purchased this calendar year as were the powder. No punctures.

Very obvious soot on the bases and only slight soot on the neck/mouth.

The bolt cleaned right up and hardly any carbon on the firing pin.

Jal5,

Have you tried any different powders? Does factory ammo do the same thing?

Jack...

I'm prolly wrong, but around the base? Case mouth yes, base no. No sir ... anneal the web and don't hit the correct temperature - hello case head separations. Anneal the mouths to 625-650 degrees

Powder - ? Would offer the burn rate is too slow and is position sensitive. Look up another recipe, reload some and compare after annealing the case mouths

factory ammo shoots clean
reloads with jacketed shoot clean too

I'd use a different powder IF I could get my hands on anything!

I'll try to anneal some cases and continue the testing with H335 will let you know how it goes. Thanks.

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Abbreviations used in Reloading
Pointed Soft Point "Core Lokt"

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